第一个 c++ 程序

double ()
{
    using namespace std;
    double nInput;
    cout << "Enter a number: ";
        cin >> nInput;
    return nInput;
}

void writeAnswer(double answer)
{
    using namespace std;
    cout << "The answer is " << answer << endl;
}

#ifndef IO_H
#define IO_H

double ();
void writeAnswer(double answer);

#endif

#include "io.h"

int main()
{
    using namespace std;
    double nInput1 = readNumber();
    double nInput2 = readNumber();
    writeAnswer(nInput1 + nInput2);
    system("pause");
    return 0;
}