Getting one too few divisors

Question

This is a program to count the number of divisors for a number, but it is giving one less divisor than there actually is for that number.

#include <stdio.h>

int i = 20;
int divisor;
int total;

int main()
{
    for (divisor = 1; divisor <= i; divisor++)
    {
        if ((i % divisor == 0) && (i != divisor))
        {
            total = total++;
        }
    }
    printf("%d %d\n", i, total);
    return 0;
}

The number 20 has 6 divisors, but the program says that there are 5 divisors.

Answer 1

&& (i != divisor)

means that 20 won't be considered a divisor. If you want it to be considered, ditch that bit of code, and you'll get the whole set, {1, 2, 4, 5, 10, 20}.

Even if you didn't want the number counted as a divisor, you could still ditch that code and just use < instead of <= in the for statement.

And:

total = total++;

is totally unnecessary. It may even be undefined, I'm just too lazy to check at the moment and it's not important since nobody writes code like that for long :-)

Use either:

total = total + 1;

or (better):

total++;