Question

当我添加或减去两个分数时，我试图显示加法和减法函数的结果。但是，每当我输入两个分数时，它都不会显示结果。它只是直接进入＆＃34;按任意键继续＆＃34;线。我想知道是否有人可以指导我解决方案。为我工作是没有必要的，但一些提示会有很大的帮助。我一直试图通过查看我的代码，使用互联网获取资源以及查看我的c ++书籍以获得一些帮助来解决这个问题。我确定我在显示功能上做错了什么。感谢您的时间。

#include <iostream>

using namespace std;

void info();
void input (int ,int ,int ,int ,int , int,char, char);
int add (int,int,int,int,int,int,char,char);
int subtract(int,int,int,int,int,int,char, char);
void display ();

int main()
{ int num1,den1,num2,den2,num_result, den_result;
  char fraction_char;
  char operation;



info();
input (num1,den1,num2,den2,num_result,den_result,fraction_char, operation);
add (num1,den1,num2,den2,num_result,den_result,fraction_char, operation);
subtract(num1,den1,num2,den2,num_result,den_result,fraction_char,operation);
display ();

    return 0;
}

void info()
{ cout<<"Please follow instructions carefully."<<endl;
   cout<<"Enter your operation like 1/2 + 1/4"<<endl;
   cout<<"You must enter a valid operation."<<endl;
   cout<<"Enter % operator to stop the program (0/1 % 0/1)"<<endl;

}

void input (int num1,int den1,int num2,int den2,int num_result, int den_result,char fraction_char, char operation)
{ cout<<"Please enter your operation."<<endl;
  cin>>num1>>fraction_char>>den1>>num2>>fraction_char>>den2;


}

int add (int num1,int den1,int num2,int den2,int num_result,int den_result,char fraction_char, char operation)
{ int addition_answer;

    if(operation== '+')
   {   num_result = (num1*den2) + (num2*den1);

       den_result = den1*den2;
      addition_answer = num_result/den_result;
   }
  return addition_answer;


}

int subtract(int num1,int den1,int num2,int den2,int num_result,int den_result, char fraction_char, char operation)
{ int subtraction_answer;


    if (operation == '-')
  { num_result = (num1*den2) - (num2*den1);
    den_result = den1*den2;
    subtraction_answer= num_result/den_result;

  }
    return subtraction_answer;
}



void display ()

{
  int num1,den1,num2,den2,num_result,den_result,fraction_char,operation;
  int fraction_added =  add (num1,den1,num2,den2,num_result,den_result,fraction_char,operation);
  int fraction_subtracted = subtract(num1,den1,num2,den2,num_result,den_result,fraction_char,operation);



  if (operation== fraction_added)

  {

  cout<<"Your answer is: "<<add;
  }

  else if (operation== fraction_subtracted)
  {
      cout<<"You answer is: "<<subtract;
  }
    add(num1,den1,num2,den2,num_result,den_result,fraction_char,operation);
    subtract(num1,den1,num2,den2,num_result,den_result,fraction_char,operation);
}

Answer 1

输入函数不返回它从cin获得的任何变量。那是因为你是按值传递函数的参数，所以它从main获取变量的副本但不能改变主变量。

要使输入函数能够更改主变量，必须更改参数，以便通过引用或指针传递。

cout调用没有多大意义：例如，看起来你在fraction_added中得到了一个结果但是却没有输出那个结果。

我试图将加法和减法函数的输出显示到显示功能中

1 个答案: