如何解決這個C++程序？

Question

我得到了我在C++類中旅行的典型距離的功課。但是，在這個問題中，老師說我不能使用「for」循環，而我只允許使用「while循環」，所以我堅持使用這個代碼。

問題是小時應顯示單獨行駛的距離，但它顯示每小時行駛的距離總量。

#include <iostream> 
using namespace std; 

int main() 
{ 
    double distance, 
      speed, 
      time, 
      counter=1; 


    cout << "This program will display the total distance travel each hour.\n\n"; 

    cout << " What is the speed of the vehicle in mph? "; 
    cin >> speed; 

    while(speed < 0) 
    { 
     cout << " Please enter a positive number for the speed: "; 
     cin >> speed; 
    } 

    cout << " How many hours has it traveled? "; 
    cin >> time; 

    while(time < 1) 
    { 
     cout << " Please enter a number greater than 1 for the hours: "; 
     cin >> time; 
    } 


    cout << endl; 
    cout << " Hour" << "\t\t" << " Distance Traveled" << endl; 
    cout << " ------------------------------------" << endl; 

    while(counter <= time) 
    { 
     distance = speed * time; 
     cout << counter << "\t\t" << distance << endl; 
     counter++; 

    } 

    return 0; 
} 

Answer 1

請嘗試，如果它真的是像距離=速度*時間一樣簡單。它看起來像變量counter和time混合起來。只需在每個增量處使用counter，即time的本地值。

#include <iostream> 
using namespace std; 

int main() 
{ 
    double distance, 
      speed, 
      time, 
      counter=1; 


    cout << "This program will display the total distance travel each hour.\n\n"; 

    cout << " What is the speed of the vehicle in mph? "; 
    cin >> speed; 

    while(speed < 0) 
    { 
     cout << " Please enter a positive number for the speed: "; 
     cin >> speed; 
    } 

    cout << " How many hours has it traveled? "; 
    cin >> time; 

    while(time < 1) 
    { 
     cout << " Please enter a number greater than 1 for the hours: "; 
     cin >> time; 
    } 


    cout << endl; 
    cout << " Hour" << "\t\t" << " Distance Traveled" << endl; 
    cout << " ------------------------------------" << endl; 

    while(counter <= time) 
    { 
     distance = speed * counter; 
     cout << counter << "\t\t" << distance << endl; 
     counter++; 

    } 

    return 0; 
} 

測試

This program will display the total distance travel each hour. 

What is the speed of the vehicle in mph? 50 
How many hours has it traveled? 5 

Hour  Distance Traveled 
------------------------------------ 
1  50 
2  100 
3  150 
4  200 
5  250 

Answer 2

假設你要計算分別爲每小時行駛的距離（從我可以從代碼中理解）;這是因爲每次在counter <= time的while循環中迭代時，都會計算該時間的距離。假設時間= 1小時，您的代碼將計算1小時內行駛的距離並顯示它。當時間爲2小時時，它將分別計算1小時和2小時內行駛的距離（總距離爲2小時）。

例：

time = 2, speed = 60 kmph 

將打印

1 60 
2 120 

其中120是在2小時內的總距離和從第一小時到第二小時不是距離。

如果您需要計算每小時行駛的距離，您的時間應該是恆定的，並且是1小時（假設速度在此期間保持不變）。爲了使用在while循環中，使用：

distance = (speed * counter) - (speed *(counter - 1)) 

距離在第n個小時行進在n個小時減去在第（n-1）小時行進距離總距離。