Cout is not a member of std in C++

Introduction

The std::cout function is a highly useful function that allows us to print data to the output console. However, we can often get errors from the compiler such as:

error: ‘cout’ is not a member of ‘std’

This error is pretty straight-forward to fix as we will see below.

Potential causes

The cout is not a member of std error could be caused by multiple reasons.

Fix #1: Add iostream to your depedencies

Essentially, the std::cout function needs to have access to the iostream module in order to be executed by the compiler.

Therefore, you must add the following #include header to the top of your code (in the include(s) part) such as:

#include <iostream> //Add this

int main() {
    std::cout << "I am using the std::cout function!";
    return 0;
}

The compiler should now recognize the std::cout function, thus fixing the cout is not a member of std error.

If the std error still persists, keep reading below.

Fix #2: Using namespace std

Note that we have previously typed: std::cout instead of cout. We can type “cout” only if we are declaring that we are using its namespace.

In other words, we would need to type “using namespace std” in the header if we only want to type cout (which is obviously shorter) instead of std::cout. For instance, we can have something like:

#include <iostream>
using namespace std; //Add this

int main() {
    cout << "I am using the std::cout function!";
    return 0;
}

It is okay to type std::cout without typing “using namespace std”. In fact, it is generally recommended to type the full std::cout function name (and therefore avoiding using namespace std) when working with multiple libraries because it can reduce future confusion.

However, if you still want to type “cout” instead of “std::cout”, then you need to add “using namespace std” to the header.

References

Read more about the std::cout function here: https://www.cplusplus.com/reference/iostream/cout/