错误：'操作符*'不匹配（操作数类型是'std :: string {aka std basic_string <char>}'和{aka std basic_string <char>}'）

Question

所以我是编程新手，这是一部分大学工程课程。我决定在课外玩得开心，写点东西。我试图用C++编写一个程序，允许用户输入3个长度，宽度和高度的矩形棱镜值，程序将使用3个值来计算棱镜的表面积和体积。

这是我到目前为止。 （用Vocareum写）

//---------------------------------------------------------------------------------------// 
//Calculate rectangular prism//   
//---------------------------------------------------------------------------------------// 
#include <string> 
#include <iostream> 
using namespace std; 

int main() 
{ 
string length; // length of prism in cm 
string width; // width of prism in cm 
string height; // height of prism in cm 

cout << "Please enter the length, width, and height of the rectangular prism." << endl; 

cin >> length; //length of prism in cm 
cin >> width; //width of prism in cm 
cin >> height; //height of prism in cm 

double volume; //volume of prism in cm^3 
double sa; //surface area of prism in cm^2 

volume = length * width * height; 
sa = (length * width * 2) + (width * height * 2) + (height * length * 2); 

cout << "The volume of the rectangular prism is " << volume << " cm^3." << endl; 
cout << "The surface area of the rectangular prism is " << sa << " cm^2." << endl; 

return 0; 
} 

//Whenever I try to compile, I'll get 4 error messages that reads 
//"error: no match for 'operator*' (operand types are 'std: :string {aka std basic_string<char>}' and {aka std basic_string<char>}') 
//ps these 3 comments aren't in the code 

我该如何解决？

Answer 1

您的length,width和height变量的类型是string，它不能被解释为数字。 如果你想它来编译只是改变他们的类型float或double（或int）