The literal meaning of `void` is *empty* or *blank*. In C, **`void`** can be used as a data type that represents *no data*.

# Usage
In C, `void` can be used as:
* `Return type` of a function that returns nothing. Consider the code snippet below, which uses `void` as a return type.





#include<stdio.h>

void sum(int a, int b){
  printf("This is a function that has no return type \n");
  printf("The function prints the sum of its parameters: %d", a + b);
}

int main() {
    
    sum(2, 5);

    return 0;
}

* `Input parameter` of a function that takes no parameters. Consider the code snippet below, which uses `void` as an input parameter.


#include<stdio.h>

int foo(void){
  printf("This is a function that has no input parameters \n");
  return 0;
}

int main() {
    
    foo();
    return 0;
}

>Note: In C, `foo()` is different from `foo(void)`. `foo()` means that the function takes an unspecified number of arguments. `foo(void)` is used for a function that takes no arguments.
* `Generic pointer` declaration that has no type specified with it. Consider the code snippet below, which uses `void` as a pointer declaration.

#include<stdio.h>
int main() {
    int a = 1;
    char b = 'B';
    float c = 3.3;

    void * ptr = &a;
    int *a2 = (int*) ptr;
    printf("The number is: %d \n", *a2);
    
    ptr = &b;
    char *b2 = (char*) ptr;
    printf("The character is: %c \n", *b2);

    ptr = &c;
    float *c2 = (float*) ptr;
    printf("The float is: %f \n", *c2);

    return 0;
}

> Note: The `void` pointer cannot be dereferenced directly. It has to be type cast to a data type before being dereferenced.

What is the void keyword in C?

Represents no data, used as a function return type, input parameter for no parameters, and generic pointer in C.