//1.14 comma operator and comma expression

//1.14 Comma operators and comma expressions

#include<stdio.h>  
int main(){

int a=2,b=4,c=6,x,y;

y=(x=a+b),(b+c);

  printf("y=%d,x=%d",y,x);
  return 0;

}

　　a=3*5,a*4
The solution to this expression , Readers may have two different understandings ： One is that “3*5,a*4” Is a comma expression , First find the value of this comma expression , If a The original value of is 3, The value of the comma expression is 12, take 12 Assign to a, So finally a The value of is 12. Another way of thinking ：“a=3*5” Is an assignment expression ”,“a*4” Is another expression , The two are connected by commas , Form a comma expression . Which of the two is right ? Assignment operators take precedence over The comma operator , So we should first solve a=3*5( That is the “a=3*5” As an expression ). After calculation and assignment, we get a The value of is 15, And then to solve a*4, have to 60. The value of the entire comma expression is 60.
　　 A comma expression can form a new comma expression with another expression , Such as (a=3*5,a*4),a+5 First calculate a The value is equal to the 15, Proceed again a*4 The operation is 60( but a The value remains the same , Still 15), Proceed again a+5 have to 20, That is, the value of the entire expression is 20.
　　 The general form of comma expression can be extended to

　　　　 expression 1, expression 2, expression 3…… expression n