将字符串乘以 const int C++

Question

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


int main() {
   
   //declaring cin inputs
   string userName;
   string userMiles;
   string userSteps;
   
   
   //declaring constant for number of steps/mile
   const int stepsPerMile = 2000;   
      
      //getting user's name
      cout << "What is the user's name?";
      cin >> userName;
      cout << endl;
      
      //getting miles walked
      cout << "How many miles did " << userName << " hike today?";
      cin >> userMiles;
      cout << endl;
      
      //getting other steps taken
      cout << "How many other steps did " << userName << " take today?";
      cin >> userSteps;
      cout << endl;
      
   string stepsTakenFromMiles;
   string totalSteps;
      
   stepsTakenFromMiles = userMiles * stepsPerMile;
   totalSteps = stepsTakenFromMiles + userSteps;
   
      cout << userName << " took " << totalSteps << " steps throughout the day." << endl;
      
   return 0;
}

我正在尝试将 userMiles（字符串）乘以 stepsPerMile（const int），但我不断收到错误消息，提示它们与操作数类型不匹配。我必须将 stepsPerMile 用作 const int 并且无法更改它。如何更改我的代码以允许将这两个输入相乘？

Answer 1

读入 userMiles 和 userSteps 作为整数，而不是字符串。 operator>> 可以读取许多不同的类型，而不仅仅是 std::string。尝试使用 int 来匹配您的 stepsPerMile 常量，例如：

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

int main() {
   
   //declaring cin inputs
   string userName;
   int userMiles;
   int userSteps;
   
   //declaring constant for number of steps/mile
   const int stepsPerMile = 2000;   
      
   //getting user's name
   cout << "What is the user's name?";
   cin >> userName;
   cout << endl;
      
   //getting miles walked
   cout << "How many miles did " << userName << " hike today?";
   cin >> userMiles;
   cout << endl;
      
   //getting other steps taken
   cout << "How many other steps did " << userName << " take today?";
   cin >> userSteps;
   cout << endl;
      
   int stepsTakenFromMiles;
   int totalSteps;
      
   stepsTakenFromMiles = userMiles * stepsPerMile;
   totalSteps = stepsTakenFromMiles + userSteps;
   
   cout << userName << " took " << totalSteps << " steps throughout the day." << endl;
      
   return 0;
}

Demo

Answer 2

一个不错的程序我检查过了。很酷的节目，我喜欢。我想解决这个问题。不要将 userMiles 设为字符串，而是将其设为像这样的 int

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


int main() {
   
   //declaring cin inputs
   string userName;
   int userMiles;
   string userSteps;
   
   
   //declaring constant for number of steps/mile
   const int stepsPerMile = 2000;   
      
      //getting user's name
      cout << "What is the user's name?";
      cin >> userName;
      cout << endl;
      
      //getting miles walked
      cout << "How many miles did " << userName << " hike today?";
      cin >> userMiles;
      cout << endl;
      
      //getting other steps taken
      cout << "How many other steps did " << userName << " take today?";
      cin >> userSteps;
      cout << endl;
      
   string stepsTakenFromMiles;
   string totalSteps;
      
   stepsTakenFromMiles = userMiles * stepsPerMile;
   totalSteps = stepsTakenFromMiles + userSteps;
   
      cout << userName << " took " << totalSteps << " steps throughout the day." << endl;
      
   return 0;
}

Answer 3

只需更改您的标识符

int userMiles, userMiles;

因为在 C++ 中你不能对字符串使用乘法运算符，这实际上可以用在其他编程语言中，例如 python 比如当你将一个字符串乘以一个数字时，字符串将重复但是在 C++ 中，您不能对字符串使用算术运算符，但“+”除外，它可用于连接 2 个或更多字符串。 This is a c++ course for beginners check it hope it helps

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