lvalue required as left operand of assignment (??)

I'm doing an example question from my C book.. a leap year is any year divisible by 4, unless it's divisible by 100 but not 400. this is what I came up with, but it won't compile. it says "leap.c:14: error: lvalue required as left operand of assignment"..

Code:

#include <stdio.h>

char line[10];
int input;

main()
{
        printf("Is this year a leap year?\nInput year: ");
        fgets(line, sizeof(line), stdin);
        sscanf(line, "%d", &input);

        if (input%4 == 0)
        {
                if ((input%100 == 0) && (input%400 =! 0))
                        printf("Is not a leap year\n");
                else printf("Is a leap year\n");
        }
        else printf("Is not a leap year\n");

        return (0);
}

anyone know what the deal is? thanks for any help!!

Code:

input%400 =! 0

Should be

Code:

input%400 != 0

Also, change

Code:

main()

to:

Code:

int main(void)

=) thankyou so so much! just brightened my evening...

Your welcome!