Functions

Functions are used to calculate values. They are almost identical to procedures — they have a name, contain instructions, and can be called to perform their actions. The only difference is what happens at the end. When a function ends, it returns a value to the caller, meaning you should call it within an expression where you want the result to be used.

A function:

• Is a building block that you can create and use in your code.
• Contains code to calculate a value. When you want this value, you call the function.
• Generally does not have a side effect - you can call it multiple times and get the same response for the game parameter values.
• Syntax is just like a procedure, with a data type instead of void.
• Are self-contained, with its instructions isolated from the other code in your program.

Examples

The code below shows an example of a function called read_string. It is passed a prompt parameter, and returns the details that the user enters at the terminal in a string. We call the function in main as part of the expression within an assignment statement.

#include "splashkit.h"

/**
* Prompt the user to enter a string, and return the value to the caller.
*
* @param prompt The message to show the user
* @returns      The data entered by the user
*/
string read_string(string prompt)
{
    string result;

    write(prompt);
    result = read_line();

    return result;
}

int main()
{
    string name;
    name = read_string("Enter your name: ");

    write_line("Hello " + name);

    return 0;
}