Why I am getting a 1 in last of my output

Because of the statement:

printf("%d", mutliply(a));

So whatever value is returned from your function will be printed. But notice that if a is non-zero on entry you do not have a matching return statement, so strictly speaking this code should not compile.

Quote:

Why I am getting a 1 in last of my output

What is weird is that this code should not compile at all.

<blockquote class="quote"><div class="op">Quote:</div>#include <stdio.h>
int mutliply(int a)
{
    if (a == 0)
    {
        return 0;
    }
    else
    {
        for (int i = 1; i < 11; i++)
        {
            int c = a * i;
            printf("%d", c);
            printf("\n");
        }
    }
    // your code is missing a return at this place
    // and it should prevent compilation.
}
int main()
{
    int a;
    printf("Enter the no. you want to write table of: ");
    scanf("%d", &a);

    printf("%d", mutliply(a));

    return 0;
}</blockquote>