Scope of Function Declarations in C

In your code, you receive a compilation error because the HelloWorld() function is not declared in the same scope as where it is called. Let's delve into the concept of function scope and resolve this issue.

Function prototypes, also known as declarations, inform the compiler about the existence of a function without providing its definition. In the given code, you are attempting to call HelloWorld() without first declaring or defining it in the current scope.

There are two ways to address this:

1. Function Declaration Before Main():

   • Add a declaration of HelloWorld() before the main function:

     void HelloWorld();

2. Function Definition Before Main():

   • Move the definition of HelloWorld() to the top of the file, before main():

     #include 
     using namespace std;
     
     void HelloWorld()
     {
     cout 

By following either of these approaches, you ensure that HelloWorld() is known to the compiler before you try to use it in main().