error function not declared in scope

Question

I'm trying to log a few values to a text file, but everytime I do it, it gives me this error:

[Error] 'save' was not declared in this scope

Here's the code:

#include "iostream"
#include "fstream"

using namespace std;
double n1, n2;

int main()
{

    n1 = 1;
    n2 = 2;
    save(n1, n2)

}
int save(double a, double b)
{
    ofstream log;
    log.open("test.txt");
    log << 1 << 2 << "\n";
    log.close();
}

I'm new to C++ and programming in general, please explain in an easy way.

Thanks.

You will get a good understanding if you read https://en.wikipedia.org/wiki/Forward_declaration — Mawg says reinstate Monica, Oct 04 '16 at 19:56
[Does function order matter in C++?](https://stackoverflow.com/questions/26122024/does-function-order-matter-in-c) — Cory Kramer, Oct 04 '16 at 19:57

krzaq · Accepted Answer · 2016-10-04T19:57:56.533

3

Code in main needs to know that such a function exists. It needs either a declaration or a definition above it:

int save(double a, double b);

int main() //...

By the way: you should eschew using global variables. And you're not using the parameters in your save function.

edited Oct 04 '16 at 19:57

answered Oct 04 '16 at 19:55

krzaq

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Dont answer this, there are 5 million duplicates to this question, you should vote to close instead. – Fantastic Mr Fox Oct 04 '16 at 19:56
Thanks for quick answer, worked just fine! – João Oct 04 '16 at 19:57
@Ben okay, I'll try. – krzaq Oct 04 '16 at 19:58

error function not declared in scope

1 Answers1