如何及時讀取輸入並格式化輸出？

我到目前爲止有：如何及時讀取輸入並格式化輸出？

cout << "Please enter your destination travel start time (HH:MM): " << endl; 
cin >>dest_startHOUR>>dest_startMIN; 

cout << "Please enter your destination travel end time (HH:MM): " << endl; 
cin >>dest_endHOUR>>dest_endMIN; 

cout << "Please enter your home travel start time (HH:MM): " << endl; 
cin >>home_startHOUR>>home_startMIN; 

cout << "Please enter your home travel end time (HH:MM): " << endl << endl; 
cin >>home_endHOUR>>home_endMIN; 
cout << "Departed from " << home_city << " at " << dest_startHOUR << ":" << dest_startMIN << "." << endl; 
cout << "Traveled " << dest_miles << " miles to " << dest_city << ", arrived at " <<  dest_endHOUR << ":" << dest_endMIN << ". " << "Travel time, " << dest_endHOUR - home_startHOUR << "." << (dest_endMIN - home_startMIN)/60 << " hours."<< endl << endl;

而且它給我下面的輸出：

Please enter your destination travel start time (HH:MM): 
04:30 
Please enter your destination travel end time (HH:MM): 
Please enter your home travel start time (HH:MM): 
Please enter your home travel end time (HH:MM): 
Departed from CityA at 4:0. 
Traveled 200 miles to CityB, arrived at 0:0. Travel time, 0.0 hours.

但我需要輸出的樣子：

Please enter your destination travel start time (HH:MM): 05:30 
Please enter your destination travel end time (HH:MM): 07:45 
Please enter your home travel start time (HH:MM): 06:15 
Please enter your home travel end time (HH:MM): 08:30 

Departed from CityA at 05:30. 
Traveled 100 miles to CityB, arrived at 
07:45. Travel time, 2.25 hours.

來源

2014-02-19 user3281580

既然你想用戶在相關提示的同一行上輸入，根據提示排除endl。您還必須忽略用戶輸入的換行符，並考慮到:字符。

試試這個：

#include <iostream> 
#include <string> 
#include <iomanip> 
#include <string> 

using namespace std; 

... 

int dest_startHOUR, dest_startMIN; 
int dest_endHOUR, dest_endMIN; 
int home_startHOUR, home_startMIN; 
int home_endHOUR, home_endMIN; 
int dest_miles; 
string home_city, dest_city; 
char c; 

... 

cout << "Please enter your destination travel start time (HH:MM): "; 
cin >> dest_startHOUR >> c >> dest_startMIN; 
cin.clear(); 
cin.ignore(numeric_limits<streamsize>::max(), '\n'); 

cout << "Please enter your destination travel end time (HH:MM): "; 
cin >> dest_endHOUR >> c >> dest_endMIN; 
cin.clear(); 
cin.ignore(numeric_limits<streamsize>::max(), '\n'); 

cout << "Please enter your home travel start time (HH:MM): "; 
cin >> home_startHOUR >> c >> home_startMIN; 
cin.clear(); 
cin.ignore(numeric_limits<streamsize>::max(), '\n'); 

cout << "Please enter your home travel end time (HH:MM): "; 
cin >> home_endHOUR >> c >> home_endMIN; 
cin.clear(); 
cin.ignore(numeric_limits<streamsize>::max(), '\n'); 

cout << endl; 
cout << "Departed from " << home_city << " at " << setw(2) << setfill('0') << dest_startHOUR << ":" << dest_startMIN << "." << endl; 
cout << "Traveled " << dest_miles << " miles to " << dest_city << ", arrived at " << setw(2) << setfill('0') << dest_endHOUR << ":" << dest_endMIN << ". " << endl; 
cout << "Travel time, " << dest_endHOUR - home_startHOUR << "." << (dest_endMIN - home_startMIN)/60 << " hours." << endl; 
cout << endl;

來源

2014-02-19 03:50:11

你能解釋一下「cin.clear的原因（）「每次後cin >>？謝謝。 –

@彭章：閱讀此：http://stackoverflow.com/questions/5131647/why-would-we-call-cin-clear-and-cin-ignore-after-reading-input –

因此，它只是爲了safefy ？考慮到這段代碼與用戶輸入大量交互。 –

你得到錯誤的結果這種情況的原因：

你把ENDL每個提示消息，這使得光標移動到下一行才把後來自用戶的響應。
當cin >> dest_startHOUR >> dest_startMIN;執行時，程序需要用戶輸入兩個整數變量（即小時和分鐘）。但是，在用戶輸入冒號後，程序將其視爲分鐘值。因此，你的程序的執行在前面，並給你不正確的結果。
您應該有（dest_endHOUR - dest_startHOUR）來計算到目的地的出發行程時間，而不是（dest_endHOUR - home_startHOUR）。
要將出發旅行時間的小數部分送到目的地，應將表達式更改爲（（dest_endMIN-dest_startMIN）/ 60.0 * 100）。您需要在60之後放置.0以避免整數除法，並且您需要將結果乘以100以將其轉換爲小時的幾分之一。但是，以HH：MM格式打印出行時間是有意義的。
如果您只考慮24小時格式，並且行程在早上開始並在當天晚上完成，那麼您的程序可以正常工作。否則，你需要增強你的代碼來考慮這個問題。

貝婁是你的程序的修訂版：

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

int main() 
{ 
    int dest_startHOUR, dest_startMIN; 
    int dest_endHOUR, dest_endMIN; 
    int home_startHOUR, home_startMIN; 
    int home_endHOUR, home_endMIN; 
    int dest_miles = 200; 
    string home_city = "CityA", dest_city = "CityB"; 
    char ch; 

    cout << "Please enter your destination travel start time (HH:MM): "; 
    cin >> dest_startHOUR >> ch >> dest_startMIN; 

    cout << "Please enter your destination travel end time (HH:MM): "; 
    cin >> dest_endHOUR >> ch >> dest_endMIN; 

    cout << "Please enter your home travel start time (HH:MM): "; 
    cin >> home_startHOUR >> ch >> home_startMIN; 

    cout << "Please enter your home travel end time (HH:MM): "; 
    cin >> home_endHOUR >> ch >> home_endMIN; 

    cout << "Departed from " << home_city << " at " << dest_startHOUR << ":" << dest_startMIN << "." << endl; 
    cout << "Traveled " << dest_miles << " miles to " << dest_city 
     << ", arrived at " << dest_endHOUR << ":" << dest_endMIN << ". " 
     << "Travel time, " << dest_endHOUR - dest_startHOUR << "." << (dest_endMIN - dest_startMIN)/60.0 * 100 
     << " hours." << endl << endl; 

    return 0; 
}

這裏看到了修訂後的程序正在運行的樣本：

Please enter your destination travel start time (HH:MM): 05:30 
Please enter your destination travel end time (HH:MM): 07:45 
Please enter your home travel start time (HH:MM): 06:15 
Please enter your home travel end time (HH:MM): 08:30 
Departed from CityA at 5:30. 
Traveled 200 miles to CityB, arrived at 7:45. Travel time, 2.25 hours.

來源

2014-02-19 05:17:23 fayez

如何及時讀取輸入並格式化輸出？

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