C++ Clrscr Was Not Declared In This Scope

5 min read Jul 01, 2024

C++ `clrscr()` Was Not Declared in This Scope: Understanding the Error and Finding Solutions

The error message "clrscr() was not declared in this scope" in C++ is a common issue faced by beginners. It indicates that the compiler doesn't recognize the clrscr() function. This is because clrscr() is not a standard C++ function, and its availability depends on the specific compiler and platform you are using.

Here's a breakdown of the problem and solutions:

Why `clrscr()` Doesn't Work in C++

Not Part of the Standard Library: clrscr() is a function primarily associated with the conio.h library, which is a non-standard library designed for console input/output operations. This library is not included in the C++ standard library.
Compiler-Specific: While conio.h might be available on certain compilers like Turbo C++, it's not guaranteed to be available in modern compilers like g++ or Visual Studio C++.

Understanding the Error Message

The compiler throws this error because it can't find the definition of clrscr(). Since it's not a standard function, the compiler cannot resolve it.

How to Fix the "clrscr() was not declared in this scope" Error

1. Avoid clrscr():

The most reliable solution is to avoid using clrscr() entirely. It's considered outdated and may not be portable across different platforms.

2. Use Alternative Methods to Clear the Console:

For Windows: Use the system("cls") function. This function executes the cls command in the command prompt, clearing the console.

#include 
#include  // For system()

int main() {
    std::cout << "This is some text.\n";
    system("cls");  // Clear the console
    std::cout << "The console is now cleared!\n";
    return 0;
}

For Linux/Unix: Use system("clear"). This executes the clear command, clearing the terminal.

#include 
#include  // For system()

int main() {
    std::cout << "This is some text.\n";
    system("clear"); // Clear the console
    std::cout << "The console is now cleared!\n";
    return 0;
}

3. Use a Standard Library Function:

Overwrite Existing Output: You can achieve a similar effect by simply outputting a large number of newline characters (\n) to push the previous content off the visible screen.

#include 

int main() {
    std::cout << "This is some text.\n";
    for (int i = 0; i < 50; ++i) {
        std::cout << '\n';  // Output newlines
    }
    std::cout << "The console is now cleared!\n";
    return 0;
}

4. Use Libraries (With Caution):

If you absolutely need clrscr() functionality, you can consider using a third-party library or header file that provides it. However, be cautious about using non-standard libraries. They might not be compatible with all compilers, and relying on them can make your code less portable.

Conclusion

The "clrscr() was not declared in this scope" error in C++ stems from the function not being part of the standard library. It's best to avoid using clrscr() and adopt the standard methods mentioned above to clear the console.

Remember, well-written C++ code adheres to standard practices, ensuring portability and compatibility across various platforms.

C++ Clrscr Was Not Declared In This Scope