Is this an correct C program?

Question

#include <stdio.h>

int main() {
    int a,b;
    a = -3--3;
    b = -3--(-3);
    printf("a=%d b=%d", a,b);
}

This program is an assignment given to us to find output. But it shows expression is not assignable

However, my other classmates got the output.

a = 0, b = -6

I don't understand how because the program feels wrong to me.

question from:https://stackoverflow.com/questions/65901985/is-this-an-correct-c-program

Answer 1

I'm guessing its just an issue of spacing your operators:

#include <stdio.h>

int main() {
    int a,b;
    a = -3 - -3;
    b = -3 - -(-3);
    printf("a=%d b=%d", a,b);
}

This gives your desired output:

a = 0, b = -6

the -- in your code is considered as a decrement operator instead of a negative sign