How do I check if an integer is even or odd?

It's the same as the title. How do I check if an integer is even or odd?

2022-09-22 14:41

1 Answers

When determining whether an integer is even or odd, there are usually two methods.

Use odd if the last bit of an integer is 1, and even if it is 0.

int c = 1;
if( c&1 )
    printf("c is odd\n");
else
    printf("c is even\n");

Definition of even and odd numbers

Use .

int c = 1;
if( c%2 )
    printf("c is odd\n");
else
    printf("c is even\n");

In the next chord, The assembly code for the two was the same, using any optimization option (without option/-O/-Os/-O2/-O3).

/* modulo.c */
#include <stdio.h>

int main(void)
{
    int x;
    for (x = 0; x < 10; x++)
        if (x % 2)
            printf("%d is odd\n", x);
    return 0;
}

/* /* and.c */
#include <stdio.h>

int main(void)
{
    int x;
    for (x = 0; x < 10; x++)
        if (x & 1)
            printf("%d is odd\n", x);
    return 0;
}

2022-09-22 14:41

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