21.How we are print even number by using for loop:

#include<stdio.h>
int main()
{
    int i,n;
    printf("Enter your choice number:");
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        if(i%2==0)
        printf("%d\t",i);
    }
    return 0;
}