堅森-學習大小事

• Integer SWAP

void swap_int(int *a, int *b)
{
    int tmp = 0;
    tmp = *a;
    *a = *b;
    *b = tmp;

    return;
}

int main(int argc, char *argv[])
{
    // 2 integer number swap
    int num_a = 25;
    int num_b = 82;
    printf("origianl: num_a=%d %x, num_b=%d %x\r\n", num_a, &num_a, num_b, &num_b);
    swap_int(&num_a, &num_b);
    printf("swap: num_a=%d %x, num_b=%d %x\r\n", num_a, &num_a, num_b, &num_b);

    return 0;
}

結果: [jenson_hu@sw6-builder3 c_string]$ ./c_reverse 
origianl: num_a=25 babf075c, num_b=82 babf0758
swap: num_a=82 babf075c, num_b=25 babf0758

• String SWAP

void swap_str(char **str_a, char **str_b)
{
    printf("=== befor exhange ==== \r\n");
    printf("function: str_a=%x *str_a=%x *str_a=%s %x\r\n", str_a, *str_a, *str_a);
    printf("funciton: str_b=%x *str_b=%x *str_b=%s  \r\n", str_b, *str_b, *str_b);
    char *tmp;
    tmp = *str_a;
    *str_a = *str_b;
    *str_b = tmp;
    printf("=== after exhange ==== \r\n");
    printf("function: str_a=%x *str_a=%x *str_a=%s \r\n", str_a, *str_a, *str_a);
    printf("funciton: str_b=%x *str_b=%x *str_b=%s \r\n", str_b, *str_b, *str_b);

    return;
}


int main(int argc, char *argv[])
{
    // The 2 string swap 
    char a[] = "apple";
    char b[] = "samsung";
    char *str_a = &a;
    char *str_b = &b;

    swap_str(&str_a, &str_b);

    return 0;
}

=== befor exhange ==== 
function: str_a=babf0738 *str_a=babf0750 *str_a=apple 3d3d2065
funciton: str_b=babf0730 *str_b=babf0740 *str_b=samsung  
=== after exhange ==== 
function: str_a=babf0738 *str_a=babf0740 *str_a=samsung 
funciton: str_b=babf0730 *str_b=babf0750 *str_b=apple