C - Logical Compound Operators

Question

Is the compound operator '&=' logical or bitwise AND ?

In other words, is a &= b the same as:

• a = a & b
• a = a && b

Answer 1

It's the bitwise AND, not the logical. (have to add some characters)

Answer 2

a &= b is using the bitwise AND operator. Think of the += operation:

a += 5;

is the same as:

a = a + 5;

It's just a combination of two operations: & and =.

Answer 3

In C, a &= b is a = a & b, i.e. bitwise. In C++, where there is a dedicated bool type, &= on booleans is boolean as well, as is a simple & on bool. None of these does exhibit the short-circuit behaviour of &&, though.

Answer 4

It's bitwise ANDsimple

When you do a&=b It means a=a&b

Remember aand bshould be integral typeor promoted to integer type

While && is logical AND.

Answer 5

This is one of the queries that can be resolved through experimentation rather than interrogation:

#include <stdio.h>
#include <inttypes.h>

int main(int argc, char *argv[]) {
    uint8_t a = 0xFF;
    uint8_t b = 0x0F;

    a &= b;
    printf("a &= b : %02X\n",a);

    a = 0xFF;
    printf("a & b : %02X\n", a & b);
    printf("a && b: %02X\n", a && b);
}

Prints:

a &= b : 0F
a & b : 0F
a && b: 01

to the console.