Array insertion

#include <stdio.h>
#include <conio.h>

void main()

{

int array[100], position, c, n, value;

printf("Enter number of elements in array\n");

scanf("%d", &n);

printf("Enter %d elements\n", n);

for ( c = 0 ; c < n ; c++ )

scanf("%d", &array[c]);

printf("Enter the location where you wish to insert an element\n");

scanf("%d", &position);

printf("Enter the value to insert\n");

scanf("%d", &value);

for ( c = n - 1 ; c >= position - 1 ; c-- )

array[c+1] = array[c];

array[position-1] = value;

printf("Resultant array is\n");

for( c = 0 ; c <= n ; c++ )

printf("%d\n", array[c]);

getch()

;

}

Array deletion

#include <stdio.h>
#include <conio.h>
void main()
{
int array[100], position, c, n;
printf("Enter number of elements in array\n");
scanf("%d", &n);
printf("Enter %d elements\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d", &array[c]);
printf("Enter the location where you wish to delete element\n");
scanf("%d", &position);
if ( position >= n+1 )
printf("Deletion not possible.\n");
else
{
for ( c = position - 1 ; c < n - 1 ; c++ )
array[c] = array[c+1];
printf("Resultant array is\n");
for( c = 0 ; c < n - 1 ; c++ )
printf("%d\n", array[c]);
}
getch();
}

hcf and lcm using function

#include <stdio.h>

long gcd(long, long);

int main() {

long x, y, hcf, lcm;

printf("Enter two integers\n");

scanf("%ld%ld", &x, &y);

hcf = gcd(x, y);

lcm = (x*y)/hcf;

printf("Greatest common divisor of %ld and %ld = %ld\n", x, y, hcf);

printf("Least common multiple of %ld and %ld = %ld\n", x, y, lcm);

return 0;

}

long gcd(long x, long y) {

if (x == 0) {

return y;

}

while (y != 0) {

if (x > y) {

x = x - y;

}

else 

{

y = y - x;

}

}

return x;

}

hcf and lcm using recursion

#include <stdio.h>

long gcd(long, long);

int main() {

long x, y, hcf, lcm;

printf("Enter two integers\n");

scanf("%ld%ld", &x, &y);

hcf = gcd(x, y);

lcm = (x*y)/hcf;

printf("Greatest common divisor of %ld and %ld = %ld\n", x, y, hcf);

printf("Least common multiple of %ld and %ld = %ld\n", x, y, lcm);

return 0;

}

long gcd(long a, long b) {

if (b == 0) {

return a;

}

else 

{

return gcd(b, a % b);

}

}

HCF & LCM

#include <stdio.h>

int main() {

int a, b, x, y, t, gcd, lcm;

printf("Enter two integers\n");

scanf("%d%d", &x, &y);

a = x;

b = y;

while (b != 0) {

t = b;

b = a % b;

a = t;

}

gcd = a;

lcm = (x*y)/gcd;

printf("Greatest common divisor of %d and %d = %d\n", x, y, gcd);

printf("Least common multiple of %d and %d = %d\n", x, y, lcm);

return 0;

}

Anagram

#include <stdio.h>
int check_anagram(char [], char []);
int main()
{
char a[100], b[100];
int flag;
printf("Enter first string\n");
gets(a);
printf("Enter second string\n");
gets(b);
flag = check_anagram(a, b);
if (flag == 1)
printf("\"%s\" and \"%s\" are anagrams.\n", a, b);
else
printf("\"%s\" and \"%s\" are not anagrams.\n", a, b);
return 0;
}
int check_anagram(char a[], char b[])
{
int first[26] = {0}, second[26] = {0}, c = 0;
while (a[c] != '\0')
{
first[a[c]-'a']++;
c++;
}
c = 0;
while (b[c] != '\0')
{
second[b[c]-'a']++;
c++;
}
for (c = 0; c < 26; c++)
{
if (first[c] != second[c])
return 0;
}
return 1;
}

Open and read file

#include <stdio.h>
#include <stdlib.h>
int main()
{
char ch, file_name[25];
FILE *fp;
printf("Enter the name of file you wish to see\n");
gets(file_name);
fp = fopen(file_name,"r"); // read mode
if( fp == NULL )
{
perror("Error while opening the file.\n");
exit(EXIT_FAILURE);
}
printf("The contents of %s file are :\n", file_name);
while( ( ch = fgetc(fp) ) != EOF )
printf("%c",ch);
fclose(fp);
return 0;
}

Copy File

#include <stdio.h>
#include <stdlib.h>
int main()
{
char ch, source_file[20], target_file[20];
FILE *source, *target;
printf("Enter name of file to copy\n");
gets(source_file);
source = fopen(source_file, "r");
if( source == NULL )
{
printf("Press any key to exit...\n");
exit(EXIT_FAILURE);
}
printf("Enter name of target file\n");
gets(target_file);
target = fopen(target_file, "w");
if( target == NULL )
{
fclose(source);
printf("Press any key to exit...\n");
exit(EXIT_FAILURE);
}
while( ( ch = fgetc(source) ) != EOF )
fputc(ch, target);
printf("File copied successfully.\n");
fclose(source);
fclose(target);
return 0;
}

File operations

#include <stdio.h>
#include <stdlib.h>
 int main()
{
FILE *fs1, *fs2, *ft;
char ch, file1[20], file2[20], file3[20];
printf("Enter name of first file\n");
gets(file1);
printf("Enter name of second file\n");
gets(file2);
printf("Enter name of file which will store contents of two files\n");
gets(file3);
fs1 = fopen(file1,"r");
fs2 = fopen(file2,"r");
if( fs1 == NULL || fs2 == NULL )
{
perror("Error ");
printf("Press any key to exit...\n");
getch();
exit(EXIT_FAILURE);
}
ft = fopen(file3,"w");
if( ft == NULL )
{
perror("Error ");
printf("Press any key to exit...\n");
exit(EXIT_FAILURE);
}
while( ( ch = fgetc(fs1) ) != EOF )
fputc(ch,ft);
while( ( ch = fgetc(fs2) ) != EOF )
fputc(ch,ft);
printf("Two files were merged into %s file successfully.\n",file3);
fclose(fs1);
fclose(fs2);
fclose(ft);
return 0;
}

View files in current directory

#include <stdio.h>
#include <conio.h>
#include <dir.h>
int main()
{
int done;
struct ffblk a;
printf("Press any key to view the files in the current directory\n");
getch();
done = findfirst("*.*",&a,0);
while(!done)
{
printf("%s\n",a.ff_name);
done = findnext(&a);
}
getch();
return 0;
}

Deletion of File

#include<stdio.h>
main()
{
int status;
char file_name[25];
printf("Enter the name of file you wish to delete\n");
gets(file_name);
status = remove(file_name);
if( status == 0 )
printf("%s file deleted successfully.\n",file_name);
else
{
printf("Unable to delete the file\n");
perror("Error");
}
return 0;
}

Random numbers

#include <stdio.h>
#include <stdlib.h>
int main() {
int c, n;
printf("Ten random numbers in [1,100]\n");
for (c = 1; c <= 10; c++) {
n = rand()%100 + 1;
printf("%d\n", n);
}
return 0;
}

Sum of complex number

#include <stdio.h>
struct complex
{
int real, img;
};
int main()
{
struct complex a, b, c;
printf("Enter a and b where a + ib is the first complex number.\n");
printf("a = ");
scanf("%d", &a.real);
printf("b = ");
scanf("%d", &a.img);
printf("Enter c and d where c + id is the second complex number.\n");
printf("c = ");
scanf("%d", &b.real);
printf("d = ");
scanf("%d", &b.img);
c.real = a.real + b.real;
c.img = a.img + b.img;
if ( c.img >= 0 )
printf("Sum of two complex numbers = %d + %di\n",c.real,c.img);
else
printf("Sum of two complex numbers = %d %di\n",c.real,c.img);
return 0;
}

Current date of your system

#include <stdio.h>
#include <conio.h>
#include <dos.h>
main()
{
struct date d;
getdate(&d);
printf("Current system date is %d/%d/%d",d.da_day,d.da_mon,d.da_year);
getch();
return 0;
}

IP of your system

#include<stdlib.h>
int main()
{
system("C:\\Windows\\System32\\ipconfig");
return 0;
}

Shutdown of your computer

#include <stdio.h>
#include <stdlib.h>
main()
{
char ch;
printf("Do you want to shutdown your computer now (y/n)\n");
scanf("%c",&ch);
if (ch == 'y' || ch == 'Y')
system("C:\\WINDOWS\\System32\\shutdown -s");
return 0;
}

ncr & npr

#include<stdio.h>
long factorial(int);
long find_ncr(int, int);
long find_npr(int, int);
main()
{
int n, r;
long ncr, npr;
printf("Enter the value of n and r\n");
scanf("%d%d",&n,&r);
ncr = find_ncr(n, r);
npr = find_npr(n, r);
printf("%dC%d = %ld\n", n, r, ncr);
printf("%dP%d = %ld\n", n, r, npr);
return 0;
}
long find_ncr(int n, int r)
{
long result;
result = factorial(n)/(factorial(r)*factorial(n-r));
return result;
}
long find_npr(int n, int r)
{
long result;
result = factorial(n)/factorial(n-r);
return result;
}
long factorial(int n)
{
int c;
long result = 1;
for( c = 1 ; c <= n ; c++ )
result = result*c;
return ( result );
}

Insertion of an element in an array

#include <stdio.h>
int main()
{
int array[100], position, c, n, value;
printf("Enter number of elements in array\n");
scanf("%d", &n);
printf("Enter %d elements\n", n);
for (c = 0; c < n; c++)
scanf("%d", &array[c]);
printf("Enter the location where you wish to insert an element\n");
scanf("%d", &position);
printf("Enter the value to insert\n");
scanf("%d", &value);
for (c = n - 1; c >= position - 1; c--)
array[c+1] = array[c];
array[position-1] = value;
printf("Resultant array is\n");
for (c = 0; c <= n; c++)
printf("%d\n", array[c]);
return 0;
}

Reverse of string

#include <stdio.h>
#include <string.h>
int main()
{
char arr[100];
printf("Enter a string to reverse\n");
gets(arr);
strrev(arr);
printf("Reverse of entered string is \n%s\n",arr);
return 0;
}

Concatination of strings

#include <stdio.h>
#include <string.h>
int main()
{
char a[100], b[100];
printf("Enter the first string\n");
gets(a);
printf("Enter the second string\n");
gets(b);
strcat(a,b);
printf("String obtained on concatenation is %s\n",a);
return 0;
}

Copy string from source to destination

#include<stdio.h>
#include<string.h>
main()
{
char source[] = "C program";
char destination[50];
strcpy(destination, source);
printf("Source string: %s\n", source);
printf("Destination string: %s\n", destination);
return 0;
}

Comparison(concatinaton) of strings

#include <stdio.h>
#include <string.h>
int main()
{
char a[100], b[100];
printf("Enter the first string\n");
gets(a);
printf("Enter the second string\n");
gets(b);
if( strcmp(a,b) == 0 )
printf("Entered strings are equal.\n");
else
printf("Entered strings are not equal.\n");
return 0;
}

Calculate length of string

#include <stdio.h>
#include <string.h>
int main()
{
char a[100];
int length;
printf("Enter a string to calculate it's length\n");
gets(a);
length = strlen(a);
printf("Length of entered string is = %d\n",length);
return 0;
}

Print entered string

#include <stdio.h>
main()
{
char array[100];
printf("Enter a string\n");
scanf("%s", array);
printf("You entered the string %s\n",array);
return 0;
}

Product of matrices

#include <stdio.h>
int main()
{
int m, n, p, q, c, d, k, sum = 0;
int first[10][10], second[10][10], multiply[10][10];
printf("Enter the number of rows and columns of first matrix\n");
scanf("%d%d", &m, &n);
printf("Enter the elements of first matrix\n");
for (  c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
scanf("%d", &first[c][d]);
printf("Enter the number of rows and columns of second matrix\n");
scanf("%d%d", &p, &q);
if ( n != p )
printf("Matrices with entered orders can't be multiplied with each other.\n");
else
{
printf("Enter the elements of second matrix\n");
for ( c = 0 ; c < p ; c++ )
for ( d = 0 ; d < q ; d++ )
scanf("%d", &second[c][d]);
for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < q ; d++ )
{
for ( k = 0 ; k < p ; k++ )
{
sum = sum + first[c][k]*second[k][d];
}
multiply[c][d] = sum;
sum = 0;
}
}
printf("Product of entered matrices:-\n");
for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < q ; d++ )
printf("%d\t", multiply[c][d]);
printf("\n");
}
}
return 0;
}

Transpose of matrix

#include <stdio.h>
int main()
{
int m, n, c, d, matrix[10][10], transpose[10][10];
printf("Enter the number of rows and columns of matrix ");
scanf("%d%d",&m,&n);
printf("Enter the elements of matrix \n");
for( c = 0 ; c < m ; c++ )
{
 for( d = 0 ; d < n ; d++ )
 {
 scanf("%d",&matrix[c][d]);
 }
 }
 for( c = 0 ; c < m ; c++ )
 {
 for( d = 0 ; d < n ; d++ )
 {
 transpose[d][c] = matrix[c][d];
 }
 }
 printf("Transpose of entered matrix :-\n");
 for( c = 0 ; c < n ; c++ )
 {
 for( d = 0 ; d < m ; d++ )
 {
 printf("%d\t",transpose[c][d]);
 }
 printf("\n");
 }
 return 0;
}

Difference of matrices

#include <stdio.h>
int main()
{
int m, n, c, d, first[10][10], second[10][10], difference[10][10];
printf("Enter the number of rows and columns of matrix\n");
scanf("%d%d", &m, &n);
printf("Enter the elements of first matrix\n");
for (c = 0; c < m; c++)
for (d = 0 ; d < n; d++)
scanf("%d", &first[c][d]);
printf("Enter the elements of second matrix\n");
for (c = 0; c < m; c++)
for (d = 0; d < n; d++)
scanf("%d", &second[c][d]);
for (c = 0; c < m; c++)
for (d = 0; d < n; d++)
difference[c][d] = first[c][d] - second[c][d];
printf("difference of entered matrices:-\n");
for (c = 0; c < m; c++)
{
for (d = 0; d < n; d++)
printf("%d\t",difference[c][d]);
printf("\n");
}
return 0;
}

Sum of matrices

#include <stdio.h>
int main()
{
int m, n, c, d, first[10][10], second[10][10], sum[10][10];
printf("Enter the number of rows and columns of matrix\n");
scanf("%d%d", &m, &n);
printf("Enter the elements of first matrix\n");
for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
scanf("%d", &first[c][d]);
printf("Enter the elements of second matrix\n");
for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
scanf("%d", &second[c][d]);
for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
sum[c][d] = first[c][d] + second[c][d];
printf("Sum of entered matrices:-\n");
for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < n ; d++ )
printf("%d\t", sum[c][d]);
printf("\n");
}
return 0;
}

Sorting in ascending order

#include <stdio.h>
int main()
{
int array[100], n, c, d, position, swap;
printf("Enter number of elements\n");
scanf("%d", &n);
printf("Enter %d integers\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d", &array[c]);
for ( c = 0 ; c < ( n - 1 ) ; c++ )
{
position = c;
for ( d = c + 1 ; d < n ; d++ )
{
if ( array[position] > array[d] )
position = d;
}
if ( position != c )
{
swap = array[c];
array[c] = array[position];
array[position] = swap;
}
}
printf("Sorted list in ascending order:\n");
for ( c = 0 ; c < n ; c++ )
printf("%d\n", array[c]);
return 0;
}

Insertion sort ascending order

#include <stdio.h>
int main()
{
int n, array[1000], c, d, t;
printf("Enter number of elements\n");
scanf("%d", &n);
printf("Enter %d integers\n", n);
for (c = 0; c < n; c++) {
scanf("%d", &array[c]);
}
for (c = 1 ; c <= n - 1; c++) {
d = c;
while ( d > 0 && array[d] < array[d-1]) {
t = array[d];
array[d]   = array[d-1];
array[d-1] = t;
d--;
}
}
printf("Sorted list in ascending order:\n");
for (c = 0; c <= n - 1; c++) {
printf("%d\n", array[c]);
}
return 0;
}

Bubble sort code

#include <stdio.h>
int main()
{
int array[100], n, c, d, swap;
printf("Enter number of elements\n");
scanf("%d", &n);
printf("Enter %d integers\n", n);
for (c = 0; c < n; c++)
scanf("%d", &array[c]);
for (c = 0 ; c < ( n - 1 ); c++)
{
for (d = 0 ; d < n - c - 1; d++)
{
if (array[d] > array[d+1]) /* For decreasing order use < */
{
swap       = array[d];
array[d]   = array[d+1];
array[d+1] = swap;
}
}
}
printf("Sorted list in ascending order:\n");
for ( c = 0 ; c < n ; c++ )
printf("%d\n", array[c]);
return 0;
}

Merge sorted arrays

#include <stdio.h>
void merge(int [], int, int [], int, int []);
int main() {
int a[100], b[100], m, n, c, sorted[200];
printf("Input number of elements in first array\n");
scanf("%d", &m);
printf("Input %d integers\n", m);
for (c = 0; c < m; c++) {
scanf("%d", &a[c]);
}
printf("Input number of elements in second array\n");
scanf("%d", &n);
printf("Input %d integers\n", n);
for (c = 0; c < n; c++) {
scanf("%d", &b[c]);
}
merge(a, m, b, n, sorted);
printf("Sorted array:\n");
for (c = 0; c < m + n; c++) {
printf("%d\n", sorted[c]);
}
return 0;
}
void merge(int a[], int m, int b[], int n, int sorted[]) {
int i, j, k;
j = k = 0;
for (i = 0; i < m + n;) {
if (j < m && k < n) {
if (a[j] < b[k]) {
sorted[i] = a[j];
 j++;
}
else
{
sorted[i] = b[k];
k++;
}
 i++;
}
else if (j == m) {
for (; i < m + n;) {
sorted[i] = b[k];
k++;
i++;
}
}
else
{
for (; i < m + n;) {
sorted[i] = a[j];
j++;
i++;
}
}
}
}

Deletion of an element in an array

#include <stdio.h>
int main()
{
int array[100], position, c, n;
printf("Enter number of elements in array\n");
scanf("%d", &n);
printf("Enter %d elements\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d", &array[c]);
printf("Enter the location where you wish to delete element\n");
scanf("%d", &position);
if ( position >= n+1 )
printf("Deletion not possible.\n");
else
{
for ( c = position - 1 ; c < n - 1 ; c++ )
array[c] = array[c+1];
printf("Resultant array is\n");
for( c = 0 ; c < n - 1 ; c++ )
printf("%d\n", array[c]);
}
return 0;
}

Insertion of an element in an array

#include <stdio.h>
int main()
{
int array[100], position, c, n, value;
printf("Enter number of elements in array\n");
scanf("%d", &n);
printf("Enter %d elements\n", n);
for (c = 0; c < n; c++)
scanf("%d", &array[c]);
printf("Enter the location where you wish to insert an element\n");
scanf("%d", &position);
printf("Enter the value to insert\n");
scanf("%d", &value);
for (c = n - 1; c >= position - 1; c--)
array[c+1] = array[c];
array[position-1] = value;
printf("Resultant array is\n");
for (c = 0; c <= n; c++)
printf("%d\n", array[c]);
return 0;
}

Reverse of an array

#include <stdio.h>
int main()
{
int n, c, d, a[100], b[100];
printf("Enter the number of elements in array\n");
scanf("%d", &n);
printf("Enter the array elements\n");
for (c = 0; c < n ; c++)
scanf("%d", &a[c]);
for (c = n - 1, d = 0; c >= 0; c--, d++)
b[d] = a[c];
for (c = 0; c < n; c++)
a[c] = b[c];
printf("Reverse array is\n");
for (c = 0; c < n; c++)
printf("%d\n", a[c]);
return 0;
}

Searching of a number (3)

#include <stdio.h>
 int main()
{
int c, first, last, middle, n, search, array[100];
printf("Enter number of elements\n");
scanf("%d",&n);
printf("Enter %d integers\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d",&array[c]);
printf("Enter value to find\n");
scanf("%d",&search);
first = 0;
last = n - 1;
middle = (first+last)/2;
while( first <= last )
{
if ( array[middle] < search )
first = middle + 1;  
else if ( array[middle] == search )
{
printf("%d found at location %d.\n", search, middle+1);
break;
}
else
last = middle - 1;
middle = (first + last)/2;
}
if ( first > last )
printf("Not found! %d is not present in the list.\n", search);
return 0;  
}

Searching of a number (2)

#include <stdio.h>
 int main()
{
int c, first, last, middle, n, search, array[100];
printf("Enter number of elements\n");
scanf("%d",&n);
printf("Enter %d integers\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d",&array[c]);
printf("Enter value to find\n");
scanf("%d",&search);
first = 0;
last = n - 1;
middle = (first+last)/2;
while( first <= last )
{
if ( array[middle] < search )
first = middle + 1;  
else if ( array[middle] == search )
{
printf("%d found at location %d.\n", search, middle+1);
break;
}
else
last = middle - 1;
middle = (first + last)/2;
}
if ( first > last )
printf("Not found! %d is not present in the list.\n", search);
return 0;  
}

Searching of a number (1)

#include <stdio.h>
 int main()
{
int c, first, last, middle, n, search, array[100];
printf("Enter number of elements\n");
scanf("%d",&n);
printf("Enter %d integers\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d",&array[c]);
printf("Enter value to find\n");
scanf("%d",&search);
first = 0;
last = n - 1;
middle = (first+last)/2;
while( first <= last )
{
if ( array[middle] < search )
first = middle + 1;  
else if ( array[middle] == search )
{
printf("%d found at location %d.\n", search, middle+1);
break;
}
else
last = middle - 1;
middle = (first + last)/2;
}
if ( first > last )
printf("Not found! %d is not present in the list.\n", search);
return 0;  
}

Location of a number to search

#include <stdio.h>
 int main()
{
int array[100], search, c, number;
printf("Enter the number of elements in array\n");
scanf("%d",&number);
printf("Enter %d numbers\n", number);
for ( c = 0 ; c < number ; c++ )
scanf("%d",&array[c]);
printf("Enter the number to search\n");
scanf("%d",&search);
for ( c = 0 ; c < number ; c++ )
{
if ( array[c] == search )     /* if required element found */
{
printf("%d is present at location %d.\n", search, c+1);
break;
}
}
if ( c == number )
printf("%d is not present in array.\n", search);    
 return 0;
}

Smallest number in an array

#include <stdio.h>
int main()
{
int array[100], minimum, size, c, location = 1;
printf("Enter the number of elements in array\n");
scanf("%d",&size);
printf("Enter %d integers\n", size);
for ( c = 0 ; c < size ; c++ )
scanf("%d", &array[c]);
minimum = array[0];
for ( c = 1 ; c < size ; c++ )
{
if ( array[c] < minimum )
{
minimum = array[c];
location = c+1;
}
}
printf("Minimum element is present at location %d and it's value is %d.\n", location, minimum);
return 0;
}

Largest number in an array

#include <stdio.h>
 int main()
{
int array[100], maximum, size, c, location = 1;
printf("Enter the number of elements in array\n");
scanf("%d", &size);
printf("Enter %d integers\n", size);
for (c = 0; c < size; c++)
scanf("%d", &array[c]);
maximum = array[0];
for (c = 1; c < size; c++)
{
if (array[c] > maximum)
{
maximum  = array[c];
location = c+1;
}
}
printf("Maximum element is present at location %d and it's value is %d.\n", location, maximum);
return 0;
}

Sum of integers

#include <stdio.h>
int main()
{
int first, second, *p, *q, sum;
printf("Enter two integers to add\n");
scanf("%d%d", &first, &second);
p = &first;
q = &second;
sum = *p + *q;
printf("Sum of entered numbers = %d\n",sum);
return 0;
}

Pascal Triangle

#include <stdio.h>
long factorial(int);
int main()
{
int i, n, c;
printf("Enter the number of rows you wish to see in pascal triangle\n");
scanf("%d",&n);
for ( i = 0 ; i < n ; i++ )
{
for ( c = 0 ; c <= ( n - i - 2 ) ; c++ )
printf(" ");
for( c = 0 ; c <= i ; c++ )
printf("%ld ",factorial(i)/(factorial(c)*factorial(i-c)));
printf("\n");
}
return 0;
}
long factorial(int n)
{
int c;
long result = 1;
for( c = 1 ; c <= n ; c++ )
result = result*c;
return ( result );
}

Floyd's triangle

#include <stdio.h>
int main()
{
int n, i,  c, a = 1;
printf("Enter the number of rows of Floyd's triangle to print\n");
scanf("%d", &n);
for (i = 1; i <= n; i++)
{
for (c = 1; c <= i; c++)
{
printf("%d ",a);
a++;
}
printf("\n");
}
return 0;
}

Fibonacci Series

#include<stdio.h>

int main()

{

int n, first = 0, second = 1, next, c;

printf("Enter the number of terms\n");

scanf("%d",&n);

printf("First %d terms of Fibonacci series are :-\n",n);

for ( c = 0 ; c < n ; c++ )

{

if ( c <= 1 )

next = c;

else

{

next = first + second;

first = second;

second = next;

}

printf("%d\n",next);

}

return 0;

}

All Armstrong numbers in a given range

#include <stdio.h>
 int main()
{
int r;
long number = 0, c, sum = 0, temp;
printf("Enter an integer upto which you want to find armstrong numbers\n");
scanf("%ld",&number);
printf("Following armstrong numbers are found from 1 to %ld\n",number);
for( c = 1 ; c <= number ; c++ )
{
temp = c;
while( temp != 0 )
{
r = temp%10;
sum = sum + r*r*r;
temp = temp/10;
}
if ( c == sum )
printf("%ld\n", c);
sum = 0;
}
return 0;
}

Armstrong number or not

#include <stdio.h>
int main()
{
int number, sum = 0, temp, remainder;
printf("Enter an integer\n");
scanf("%d",&number);
temp = number;
while( temp != 0 )
{
remainder = temp%10;
sum = sum + remainder*remainder*remainder;
temp = temp/10;
}
if ( number == sum )
printf("Entered number is an armstrong number.\n");
else
printf("Entered number is not an armstrong number.\n");
return 0;
}

graphics 1

#include<graphics.h>
#include<conio.h>
#include<dos.h>
void ui();
int condition();
void showmouseptr();
void getmousepos();
union REGS i, o;
void main()
{
int gd = DETECT, gm, status, button, x, y,i,j,col=1;
char array[50];
initgraph(&gd,&gm,"C:\\TC\\BGI");
status = initmouse();
if ( status == 0 )
printf("Mouse support not available.\n");
else
{
gotoxy(77,25);
printf("E");
for(j=0;j<=417;j++)
{
setcolor(WHITE);
rectangle(10,47+j,2+j+170,47);
}
ui();
showmouseptr();
getmousepos(&button,&x,&y);
while(!kbhit())
{
getmousepos(&button,&x,&y);
col=condition(x,y);
if( button == 1 )
{
if((((x>600)&&(x<635))&&((y>1)&&(y<35))))
exit(1);
else if(((y>50)&&(x<635))&&((x>20)))
{
if(col==1)
setcolor(RED);
else if(col==2)
setcolor(YELLOW);
else if(col==3)
setcolor(GREEN);
else if(col==4)
setcolor(BLUE);
else if(col==5)
setcolor(WHITE);
else if(col==6)
setcolor(CYAN);
for(i=0;i<=10;i++)
{
circle(x,y,i);
}
button = -1;
}
}
}
}
getch();
}
int initmouse()
{
i.x.ax = 0;
int86(0X33,&i,&o);
return ( o.x.ax );
}
void showmouseptr()
{
i.x.ax = 1;
int86(0X33,&i,&o);
}
void getmousepos(int *button, int *x, int *y)
{
i.x.ax = 3;
int86(0X33,&i,&o);
*button = o.x.bx;
*x = o.x.cx;
*y = o.x.dx;
}
void ui()
{
int j;
rectangle(1,1,637,35);
gotoxy(35,2);printf("MJ Paint");
rectangle(600,1,637,35);
gotoxy(78,2);printf("X");
rectangle(600,45,635,260);
setcolor(RED);
rectangle(605,50,630,80);
setcolor(YELLOW);
rectangle(605,85,630,115);
setcolor(GREEN);
rectangle(605,120,630,150);
setcolor(BLUE);
rectangle(605,155,630,185);
setcolor(WHITE);
rectangle(605,190,630,220);
setcolor(CYAN);
rectangle(605,225,630,255);
setcolor(WHITE);
rectangle(600,380,630,400);
}
int condition(int x,int y)
{
int clr;
if(((x>605)&&(y>50))&&((x<630)&&(y<80)))
{
clr=1;
}
if(((x>605)&&(y>85))&&((x<630)&&(y<115)))
{
clr=2;
}
if(((x>605)&&(y>120))&&((x<630)&&(y<150)))
{
clr=3;
}
if(((x>605)&&(y>155))&&((x<630)&&(y<185)))
{
clr=4;
}
if(((x>605)&&(y>190))&&((x<630)&&(y<225)))
{
clr=5;
}
if(((x>605)&&(y>225))&&((x<630)&&(y<255)))
{
clr=6;
}
if(((x>605)&&(y>380))&&((x<630)&&(y<400)))
{
clr=5;
}
return(clr);
}

Guess output 2

#include<stdio.h>
int main()
{
int n, i = 3, count, c;
printf("Enter the number of prime numbers required\n");
scanf("%d",&n);
if ( n >= 1 )
{
printf("First %d prime numbers are :\n",n);
printf("2\n");
}
for ( count = 2 ; count <= n ;  )
{
for ( c = 2 ; c <= i - 1 ; c++ )
{
if ( i%c == 0 )
break;
}
if ( c == i )
{
printf("%d\n",i);
count++;
}
i++;
}
return 0;
}

guess output

#include <stdio.h>
int main()
{
int n, c, k, space = 1;
printf("Enter number of rows\n");
scanf("%d", &n);
space = n - 1;
for (k = 1; k <= n; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space--;
for (c = 1; c <= 2*k-1; c++)
printf("*");
printf("\n");
}
space = 1;
for (k = 1; k <= n - 1; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space++;
for (c = 1 ; c <= 2*(n-k)-1; c++)
printf("*");
printf("\n");
}
 return 0;
}

Pyramid of stars

#include <stdio.h>
 int main()
{
int row, c, n, temp;
printf("Enter the number of rows in pyramid of stars you wish to see ");
scanf("%d",&n);
temp = n;
for ( row = 1 ; row <= n ; row++ )
{
for ( c = 1 ; c < temp ; c++ )
printf(" ");
temp--;
for ( c = 1 ; c <= 2*row - 1 ; c++ )
printf("*");
printf("\n");
}
return 0;
}

Palindrome or not

#include <stdio.h>
 int main()
{
int n, reverse = 0, temp;
printf("Enter a number to check if it is a palindrome or not\n");
scanf("%d",&n);
temp = n;
while( temp != 0 )
{
reverse = reverse * 10;
reverse = reverse + temp%10;
temp = temp/10;
}
if ( n == reverse )
printf("%d is a palindrome number.\n", n);
else
printf("%d is not a palindrome number.\n", n);
return 0;
}

Reverse of entered number

#include <stdio.h>
int main()
{
int n, reverse = 0;
printf("Enter a number to reverse\n");
scanf("%d",&n);
while (n != 0)
{
reverse = reverse * 10;
reverse = reverse + n%10;
n = n/10;
}
printf("Reverse of entered number is = %d\n", reverse);
return 0;
}

Swapping of two number

#include <stdio.h>
int main()
{
int x, y, temp;
printf("Enter the value of x and y\n");
scanf("%d%d", &x, &y);
printf("Before Swapping\nx = %d\ny = %d\n",x,y);
temp = x;
x    = y;
y    = temp;
printf("After Swapping\nx = %d\ny = %d\n",x,y);
return 0;
}

Sum of integer

#include <stdio.h>
int main()
{
int n, sum = 0, c, value;
printf("Enter the number of integers you want to add\n");
scanf("%d", &n);
printf("Enter %d integers\n",n);
for (c = 1; c <= n; c++)
{
 scanf("%d",&value);
 sum = sum + value;
 }
 printf("Sum of entered integers = %d\n",sum);
 return 0;
}

ncr and npr

#include<stdio.h>
long factorial(int);
long find_ncr(int, int);
long find_npr(int, int);
main()
{
int n, r;
long ncr, npr;
printf("Enter the value of n and r\n");
scanf("%d%d",&n,&r);
ncr = find_ncr(n, r);
npr = find_npr(n, r);
printf("%dC%d = %ld\n", n, r, ncr);
printf("%dP%d = %ld\n", n, r, npr);
return 0;
}
long find_ncr(int n, int r)
{
long result;
result = factorial(n)/(factorial(r)*factorial(n-r));
return result;
}
 long find_npr(int n, int r)
{
long result;
result = factorial(n)/factorial(n-r);
return result;
}
long factorial(int n)
{
int c;
long result = 1;
for( c = 1 ; c <= n ; c++ )
result = result*c;
return ( result );
}

decimal to binary conversion

#include <stdio.h>
int main()
{
int n, c, k;
printf("Enter an integer in decimal number system\n");
scanf("%d", &n);
printf("%d in binary number system is:\n", n);
for (c = 31; c >= 0; c--)
{
k = n >> c;
if (k & 1)
printf("1");
else
printf("0");
}
printf("\n");
return 0;
}

GCD and LCM

#include <stdio.h>
int main() {
int a, b, x, y, t, gcd, lcm;
printf("Enter two integers\n");
scanf("%d%d", &x, &y);
a = x;
b = y;
while (b != 0)
{
t = b;
b = a % b;
a = t;
}
gcd = a;
lcm = (x*y)/gcd;
printf("Greatest common divisor of %d and %d = %d\n", x, y, gcd);
printf("Least common multiple of %d and %d = %d\n", x, y, lcm);
return 0;
}

Factorial of a number

#include <stdio.h>
int main()
{
int c, n, fact = 1;
printf("Enter a number to calculate it's factorial\n");
scanf("%d", &n);
for (c = 1; c <= n; c++)
fact = fact * c;
printf("Factorial of %d = %d\n", n, fact);
return 0;
}

Sum of number

#include <stdio.h>
int main()
{
int n, sum = 0, remainder;
printf("Enter an integer\n");
scanf("%d",&n);
while(n != 0)
{
remainder = n % 10;
sum = sum + remainder;
n = n / 10;
}
printf("Sum of digits of entered number = %d\n",sum);
return 0;
}

Leap Year

#include <stdio.h>
int main()
{
int year;
printf("Enter a year to check if it is a leap year\n");
scanf("%d", &year);
if ( year%400 == 0)
printf("%d is a leap year.\n", year);
else if ( year%100 == 0)
printf("%d is not a leap year.\n", year);
else if ( year%4 == 0 )
printf("%d is a leap year.\n", year);
else
printf("%d is not a leap year.\n", year);
return 0;
}

Vowel or not

#include <stdio.h>
int main()
{
char ch;
printf("Enter a character\n");
scanf("%c", &ch);
if (ch == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i' || ch == 'I' || ch =='o' || ch=='O' || ch == 'u' || ch== 'U')
printf("%c is a vowel.\n", ch);
else
printf("%c is not a vowel.\n", ch);
return 0;
}

Simple calculator

#include <stdio.h>
int main()
{
int first, second, add, subtract, multiply;
float divide;
printf("Enter two integers\n");
scanf("%d%d", &first, &second);
add        = first + second;
subtract = first - second;
multiply = first * second;
divide     = first / (float)second;   //typecasting
printf("Sum = %d\n",add);
printf("Difference = %d\n",subtract);
printf("Multiplication = %d\n",multiply);
printf("Division = %.2f\n",divide);
return 0;
}

Even or odd

#include<stdio.h>
int main()
{
int n;
printf("Enter an integer\n");
scanf("%d",&n);
if ( n%2 == 0 )
printf("Even\n");
else
printf("Odd\n");
return 0;
}

Addition of two numers

#include<stdio.h>
int main()
{
int a, b, c;
printf("Enter two numbers to add\n");
scanf("%d%d",&a,&b);
c = a + b;
printf("Sum of entered numbers = %d\n",c);
return 0;
}

Print entered number

#include <stdio.h>

int main()
{
  int a;

  printf("Enter an integer\n");
  scanf("%d", &a);

  printf("Integer that you have entered is %d\n", a);

  return 0;
}