Bitwise can be used to reverse a sign of a number.

#include<stdio.h>
#include<stdlib.h>

union employee
{
    char name[15];
    int age;
    float salary;
};
const union employee e1;

int main()
{
    strcpy(e1.name, "K");
    printf("%s", e1.name);    
    e1.age=85;
    printf("%d", e1.age);
    printf("%f", e1.salary);
    return 0;
}

#include<stdio.h>
const char *fun();

int main()
{
    char *ptr = fun();
    return 0;
}
const char *fun()
{
    return "Hello";
}

#include<stdio.h>
#define MAX 128

int main()
{
    const int max=128;
    char array[max];
    char string[MAX];
    array[0] = string[0] = 'A';
    printf("%c %c\n", array[0], string[0]);
    return 0;
}