為什么我在 C++ 中的 function 沒有被執行？

Question

我有一個 C++ 實驗室，問題是：用戶應該為 X 輸入一個值（X 是舉行的測試次數）。 如果 x<15，程序不計算任何東西。 如果 X 介於 16 和 30 之間，則程序應計算 C=1.0/10.0*(24 A)，如果 X>30，則程序應計算 C=0.15 (24*A)。 我的多個 if 代碼有效，但是當我輸入 X 的值時，方程未解。 有人有什么主意嗎？？

#include<iostream>
#include<cmath>

#define _USE_MATH_DEFINES

using namespace std;

int main()
{
    //variables defined here
    float A, X, C, F;
    //A stands for number of classes scheduled

    //X is for number of tests and C is the modification 

    cout << "This program predicts the number of cars parked at HVCC at any given hour \n";
    cout << "enter a value for A \n";
    cin >> A;

    cout << "enter a value for number of tests X \n";
    cin >> X;

    if (X < 15)
    {
        cout << "No modificatons needed for under 15 tests \n";
    }

    else if (X > 15 && X < 20)
    {
        cout << "Approximation for between 15-30 tests \n";
        C = 1.0 / 10.0 * (24 * A);
        cin >> C;
    }

    else
    {
        cout << "Approximation for more than 30 tests \n";
        C = 0.15 * (24 * A);
        cin >> C;
    }
}

Answer 1

使用cin可以讀取用戶輸入。 使用cout打印結果：

#include<iostream>
#include<cmath>

#define _USE_MATH_DEFINES

using namespace std;

int main()
{
    //variables defined here
    float A, X, C, F;
    //A stands for number of classes scheduled

    //X is for number of tests and C is the modification 

    cout << "This program predicts the number of cars parked at HVCC at any given hour \n";
    cout << "enter a value for A \n";
    cin >> A;

    cout << "enter a value for number of tests X \n";
    cin >> X;

    if (X < 15)
    {
        cout << "No modificatons needed for under 15 tests \n";
    }

    else if (X > 15 && X < 20)
    {
        cout << "Approximation for between 15-30 tests \n";
        C = 1.0 / 10.0 * (24 * A);
        cout << C; // replace cin >> with cout <<
    }

    else
    {
        cout << "Approximation for more than 30 tests \n";
        C = 0.15 * (24 * A);
        cout << C; // replace cin >> with cout <<
    }
}

Answer 2

cin >> C; will get the user input for C.

在兩個 else 塊中將其更改為cout << C 。