c++ - 未定义对`saving::rate'的引用

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我正在编写此代码，但是当我在Arch Linux中用g ++编译此代码时，我收到此错误

  /tmp/ccG7axw1.o: In function `saving::calculate()':
  saving.cpp:(.text+0x3a): undefined reference to `saving::rate'
  /tmp/ccG7axw1.o: In function `saving::modify()':
  saving.cpp:(.text+0x93): undefined reference to `saving::rate'
  collect2: error: ld returned 1 exit status

保存.h

class saving{
private :
    double savebal;
public :
    saving(double newSavebal);
    double calculate();
    void modify();
    static double rate;
};

Saving.cpp

#include<iostream>
#include"saving.h"
using namespace std;
saving :: saving(double newSavebal){
   savebal = newSavebal;
}
double saving :: calculate(){
    savebal += (savebal * (rate / 100))/12;
}

void saving :: modify(){
    cout<<"Please enter the new rate"<<endl;
    cin>>rate;
}

mainSaving.cpp

#include<iostream>
#include"saving.h"
using namespace std;
void menu(saving );
int main(){
      saving s1(500);
      menu(s1);
}

  void menu(saving s){
    int m;
    cout<<"1) calculate month interest\n";
    cout<<"2) change rate of interest\n";
    cin>>m;
    switch(m){
        case 1 :
         s.calculate();
         break;
        case 2 :
         s.modify();
         break;

    }
}

最佳答案

在Saving.h中，您声明了静态变量：

static double rate;

但是您仍然需要定义它（换句话说，实例化它）。为此，您应该将此添加到Saving.cpp：

 double saving::rate = 0;

否则，链接器将找不到实际的变量，因此对它的任何引用都将导致链接器错误。

关于c++ - 未定义对`saving::rate'的引用，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/42961807/