Question

我对c ++很陌生并且正在搞乱函数。我似乎无法弄清楚为什么下面的代码不起作用，任何帮助将不胜感激。

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;

int main() {
    movieOutput("Hello");

    return 0;
}

//This is just for a little extra versatility
int movieOutput(string movieName,int aTix = 0,int cTix = 0,float grPro = 0.0,float nePro = 0.0,float diPro = 0.0){

    //I don't understand whether I should declare the arguments inside the 
    //functions parameters or in the function body below.

    /*string movieName;
      int aTix = 0, cTix = 0;
      float grPro = 0.0, nePro = 0.0, diPro = 0.0;*/

    cout << "**********************Ticket Sales********************\n";
    cout << "Movie Name: \t\t" << movieName << endl;
    cout << "Adult Tickets Sold: \t\t" << aTix << endl;
    cout << "Child Tickets Sold: \t\t" << aTix << endl;
    cout << "Gross Box Office Profit: \t" << grPro << endl;
    cout << "Net Box Office Profit: \t" << nePro << endl;
    cout << "Amount Paid to the Distributor: \t" << diPro << endl;

    return 0;
}

构建错误我正在

`Build:(compiler: GNU GCC Compiler)
|line-8|error: 'movieOutput' was not declared in this scope|
Build failed: 1 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|`

Answer 1

你提出了

的前瞻声明

int movieOutput(string movieName,int aTix = 0,int cTix = 0,
                float grPro = 0.0,float nePro = 0.0,float diPro = 0.0);

出现在main()之前。

默认参数也需要在函数声明中而不是定义签名。

这里是固定代码：

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;

int movieOutput(string movieName,int aTix = 0,int cTix = 0,
                float grPro = 0.0,float nePro = 0.0,float diPro = 0.0);

int main() {
    movieOutput("Hello");

    return 0;
}

//This is just for a little extra versatility
int movieOutput(string movieName,int aTix,int cTix,float grPro,float nePro,float diPro){

    cout << "**********************Ticket Sales********************\n";
    cout << "Movie Name: \t\t" << movieName << endl;
    cout << "Adult Tickets Sold: \t\t" << aTix << endl;
    cout << "Child Tickets Sold: \t\t" << aTix << endl;
    cout << "Gross Box Office Profit: \t" << grPro << endl;
    cout << "Net Box Office Profit: \t" << nePro << endl;
    cout << "Amount Paid to the Distributor: \t" << diPro << endl;

    return 0;
}

Answer 2

在调用之前声明你的函数x）

int movieOutput(string, int, int, float, float, float); // function prototype 

int main()... 

int movieOutput(...) { /* declaration goes here */}

或者只是简单地将整个函数声明放在主

之前

我的职能有什么问题

2 个答案: