c++ 师。看似简单的事情让我发疯，请指教

Question

好的，我已经编程了大约一个星期了，我是从 C++ 开始的。我正在编写一个程序，它是一种算术训练器，你输入你想要的方程式的数量，你输入你对随机数生成器的限制，你指定你想要什么样的方程式(/* - +)，然后该程序使用 for 循环并遍历并在 var 中生成方程式及其答案，然后根据该 var 检查用户输入，如果它们与另一个 var 匹配，则计算正确答案的值将递增。在最后一个等式之后，程序会告诉用户他们从多少个等式中答对了多少个，然后将正确答案的数量除以问题的数量，然后将该值乘以 100 u 应该得到该用户算术 session 的准确率.问题是 c++ 一直返回给我一个该死的 0 值，我一辈子都弄不明白为什么 c++ 会这样做。

整个程序:

#include <iostream>
#include <string>
#include <ctime>
#include <cstdlib>
using namespace std;
void menu(void);
class session{
public:
session(){
            create_session();
        }
        void create_session(void){
        amount = 0;
        range_limit = 0;
        rights = 0;
        answer = 0;
        input = 0;
        type = "";
        while(amount == 0){
            cout << "\nHow many equations do you want?: "; cin >> amount;
            if(amount < 1){
                cout << "\nAmount is too low!";
                amount = 0;
            }
        }
        while(range_limit == 0){
            cout << "Enter the number range limit: "; cin >> range_limit;
            if(range_limit < 1){
                cout << "\nRange limit too low!";
                range_limit = 0;
            }
        }
        while(type == ""){
            cout << "What equation type do you want?: "; cin >> type;
            int strlen = type.size();
            if(strlen < 1){
                cout << "Invalid type input!";
                type = "";
            }
        }
        if(type == "+"){
            for(int i=0;i<amount;i++){
                int a = random();
                int b = random();
                answer = a + b;
                cout << "\n" << a << " + " << b << " = "; cin >> input;
                if(answer == input){
                    rights++;
                }
            }
        }
cout << "\nYou got " << rights << " answers right out of " << amount <<         " equations." << endl;
        cout << "Accuracy percentage: " << getAccuracy() << "%" << endl;
        int post_menu=0;
        while(post_menu == 0){
            cout << "Enter 1 to create another session or 2 to return to the menu: ";
            cin >> post_menu;
            if(post_menu == 1){
                create_session();
            }else if(post_menu == 2){
                menu();
            }else{
                cout << "Invalid input: ";
                post_menu = 0;
            }
        }
    }
    float getAccuracy(){
           float x = (rights/amount)*100;
           return x;
    }
    int random(){
        int x = 1+(rand()%range_limit);
        return x;
    }
    void set_amount(int a){
        amount = a;
    }
    void set_range_limit(int r){
        range_limit = r;
    }
    void set_rights(int R){
        rights = R;
    }
    void set_answer(int a){
        answer = a;
    }
    void set_input(int i){
        input = i;
    }
    void set_type(string t){
        type = t;
    }
private:
    int amount;
    int accuracy;
    int range_limit;
    int rights;
    int answer;
    int input;
    string type;

};
int main(){
cout << "=== WELCOME TO ARITH! === \n=========================\n";
menu();
return 0;
}

void menu(void){
//Set the seed for random number gen.
srand(time(0));

 //Set var for getting menu input, then get the menu input..
 int menu_input;
 cout << "\n[1]Create a Session. [2]Exit Arith. \nWhat would you like to do?: ";
 cin >> menu_input;

 //Now we check what the user wants and act accordingly..
 if(menu_input > 2){
    cout << "error";
    menu_input=0;
 }else if(menu_input == 1){
     session start;
 }else if(menu_input == 2){
    cout << "\nExiting Arith!";
 }else{
    cout << "error";
    menu_input=0;
 }
}

麻烦的部分:

    float getAccuracy(){
           float x = (rights/amount)*100;
           return x;

一些程序如何返回 0%。

任何人都知道为什么会这样以及如何得到结果。

Answer 1

rights 和 amount 都是 int ，所以当你划分值(value)时，例如如果你做 5/2 答案将是 2 而不是 2.5。要解决此问题，您需要将其中一个变量转换为 float，如下所示:(float(rights)/amount) * 100。