Logical operator of C language

A logical operator:

&&: Logic and, Read and

Expressions are true on both sides of the expression, so the result is true.

Formula: a false or False

|| : logical OR, read or

Expression the left and right sides, there is a true, then the result is true

Formula: One true is true

!: Logical not, read as reverse

If the result of an expression is false, it becomes true, and if it is true, it becomes false.

Formula: True change false, false change true

Short-circuit problem of two logical operators

Tips: Not 0 is true, 0 is False

Short-Circuit Condition:

&&: Left If False, the right short circuit (right will not be executed)

|| : If true on left, short to right (not on right)

Tips: Code examples are as follows

#include <stdio.h>

int main (int argc, const char * argv[]) {

int res = 1 && 2;

printf ("res=%d\n", res);

int res = 1 &&-2;

printf ("res=%d\n", res);//1

int res = 1 && 0;

printf ("res=%d\n", res);//0

int num1=10,num2=20;

Or the formula: a true true, so if the left is true, then the right expression will not be executed

int res = num1++ | | num2++;

printf ("res=%d num1=%d num2=%d\n", res,num1,num2);//1 11 20

int num1=0,num2=10;

And the formula: a false is false

int res = num1++ && num2++;

printf ("res=%d num1=%d num2=%d\n", res,num1,num2); 0 1 10

int num1=0,num2=10;

int sum = num1++ + num2; 10

int num = 10;

int res = 0 && num++;

printf ("res=%d num=%d\n", res,num); 0 10

int num1=0,num2=10;

And the formula: a false is false

int res = NUM1 && num2++;

printf ("res=%d num1=%d num2=%d\n", res,num1,num2); 1 1 11

int num1=-3,num2=3,num3=4;

int res = (NUM1 + num2) && (NUM1-NUM3);

printf ("res=%d\n", res);//0

int num1=-3,num2=3,num3=4;

int res = (NUM1 + num2) && num3++;

printf ("res=%d num3=%d\n", res,num3);//0 4

int num1=-3,num2=3,num3=4;

int res = num1++ + num2++ && num3++;

printf ("res=%d num1=%d num2=%d num3=%d\n", res,num1,num2,num3);//0-2 4 4

return 0;

}

Logical operator of C language