Check if Vowel 0r not
#include <stdio.h> int main()
{
char ch; printf("Input a character\n"); scanf("%c", &ch); switch(ch) { case 'a': case 'A': case 'e': case 'E': case 'i': case 'I': case 'o': case 'O': case 'u': case 'U': printf("%c is a vowel.\n", ch); break; default: printf("%c is not a vowel.\n", ch); } return 0;
}
Leap Year or Not
#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;
}

Add Digits

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

Greatest Common divisor and Least Common Multiple
#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;
}

#include <stdio.h> int main()
{
int n, reverse=0, rem; printf("Enter an integer: "); scanf("%d", &n); while(n!=0) { rem=n%10; reverse=reverse*10+rem; n/=10; } printf("Reversed Number = %d",reverse); return 0;
}