Please Explain Comma Operator in this Program

Question

Please explain me the output of this program:

int main()
{    
    int a,b,c,d;  
    a=10;  
    b=20;  
    c=a,b;  
    d=(a,b);  
    printf(\"\\nC= %d\"         


        

Answer 1

The comma operator evaluates all its operands, then yields the value of the last expression.

Answer 2

The , operator evaluates a series of expressions and returns the value of the last.

c=a,b is the same as (c=a),b. That is why c is 10

c=(a,b) will assign the result of a,b, which is 20, to c.

As Mike points out in the comments, assignment (=) has higher precedence than comma

Answer 3

Well, this is about operator precedence:

c=a,b

is

equivalent to

(c=a),b

The point is, the "," operator will return the second value.

Thus

c=a,b

assigns a to c and returns b

d=(a,b) 

returns b and assigns it to d