Assignment operator works fine as a condition in if Statement in C programs

Question

I am aware that when a non zero value is provided as a condition in an if statement, the condition is evaluated to be true.

Yet, I'm wondering how an assignment(=) is evaluated to be true here, instead of a comparison(==), and runs without any errors in the below C program.

int main(){
int a, b =5;

if(a=10) {
   ("This works");
}

if(b=1){
   ("This works too");
} }

Answer 1

1. a = 10 is an expression that assigns 10 to a and whose value is the result of the assignment (that is 10).

2. any value different from 0 is considered to be true

Try this:

if (b = 0) {
   ("This is never displayed");
}

Answer 2

The assignment operator always returns the value that was assigned. So in your case a=10 has the value 10 and the if statement is essentially if(10). Which is true.