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Home Backend Development C++ Why am I getting the \'HelloWorld() was not declared in this scope\' error in my C code?

Why am I getting the \'HelloWorld() was not declared in this scope\' error in my C code?

Oct 27, 2024 am 10:13 AM

Why am I getting the

Undeclared Function in Scope: Resolving 'HelloWorld' Error

In the C code snippet provided, you encounter a compilation error with the message "HelloWorld() was not declared in this scope." This error occurs when a function call is made without proper declaration or definition in the current scope.

To resolve this issue, you need to either declare the function's prototype using the function's return type and parameters or define the function before you use it. By providing a function declaration, you inform the compiler that the function exists, even if its definition is not yet provided.

In your specific case, you have defined the function HelloWorld() after main(). One solution is to move the function definition before main():

<code class="cpp">#include <iostream>
using namespace std;

void HelloWorld()
{
    cout << "Hello, World" << endl;
}

int main()
{
    HelloWorld();
    return 0;
}</code>

Alternatively, you can declare the function's prototype before main():

<code class="cpp">#include <iostream>
using namespace std;

void HelloWorld();

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

void HelloWorld()
{
    cout << "Hello, World" << endl;
}</code>

By following these steps, you can ensure that the HelloWorld() function is declared or defined before it is called, thereby resolving the compilation error.

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