Why does the program only give an output if defined in main (and how can I change this)?

Question

I tried to run this

int array( void )
{
    char text[12] = {  112, 114, 111, 103, 112, 0 };
    int i;
    for(i = 0; text[i]; i = i +1)
        printf("%c", text[i]);
    printf("\n");
    return 0;
}

int main( void )
{
    int array(void);
    return 0;
}

and the program runs but I am getting no result. Now when I use the main function to define the program:

int main( void )
{
    char text[12] = {  112, 114, 111, 112, 0 };
    int i;
    for(i = 0; text[i]; i = i +1)
        printf("%c", text[i]);
    printf("\n");
    return 0;
}

I get the result progr(as wanted). I already searched but the only related questions I find are about using main as a function name and wrong outputs. Maybe I am searching the wrong way but I would be pleased if someone could answer this.

Answer 1

Your direct problem is that you did not call the function array, you declare it inside the body of main. The declaration itself does not execute the code.

A function declaration tells the compiler about a function's name, return type, and parameters.

A function definition provides the actual body of the function.

Defining a Function

The general form of a function definition in C programming language is as follows

return_type function_name( parameter list ) {
   body of the function
}

In your case you have two function definitions:

// 1.
int array( void )
{
    char text[12] = {  112, 114, 111, 103, 112, 0 };
    int i;
    for(i = 0; text[i]; i = i +1)
        printf("%c", text[i]);
    printf("\n");
    return 0;
}

// 2.
int main(void)
{
    //...
    return 0;
}

Function Declarations

A function declaration tells the compiler about a function name and how to call the function. The actual body of the function can be defined separately.

int array(void); // function declaration, no parameters, returns int value 

Calling a Function

To call a function, you simply need to pass the required parameters along with the function name, and if the function returns a value, then you can store the returned value.

In your case call it like this:

 array();

since there are no parameters to pass.

To sum up:

int array(void);   // function declaration, no parameters, returns int value 

int array(void)    // definition of the function `array`
{   
    // function body
    char text[12] = {  112, 114, 111, 103, 112, 0 };
    // ...
    return 0;
}   

int main(void)    // definition of the function `main`, 
{
  array();        // function call, calling function `array` with no parameters
  return 0;
}