I need help printing a queue in a header.h file (c++)

Question

I need help printing a queue in a header.h file.

for example: this works just fine:

main.cpp

void showq(queue<int> gq)
{
    queue<int> g = gq;
    while (!g.empty()) {
        cout << '\t' << g.front();
        g.pop();
    }
    cout << '\n';
}


int main()
{

   queue<int> gquiz;
   gquiz.push(10);
   gquiz.push(20);
   gquiz.push(30);

   showq(gquiz);



    return 0;
}

Output: 10 20 30

but this does not

main.cpp

int main()
{

   queue<int> gquiz;
   gquiz.push(10);
   gquiz.push(20);
   gquiz.push(30);

   showq(gquiz);



    return 0;
}

header.h:

void showq(queue<int> gq)
{
    queue<int> g = gq;
    while (!g.empty()) {
        cout << '\t' << g.front();
        g.pop();
    }
    cout << '\n';
}

Output: error: variable or field showq declared void

Answer 1

Have you forget to add #include "header.h" in main.cpp?

main.cpp:

#include "header.h"
int main()
{

   queue<int> gquiz;
   gquiz.push(10);
   gquiz.push(20);
   gquiz.push(30);

   showq(gquiz);



    return 0;
}

By the way, perhaps it's a better way to declare your showq function in header.h:

#include <queue>

void showq(queue<int> gq);

And then define it in header.cpp:

#include "header.h"

void showq(queue<int> gq)
{
    queue<int> g = gq;
    while (!g.empty()) {
        cout << '\t' << g.front();
        g.pop();
    }
    cout << '\n';
}