所以,我有幾個字段填入數字。如果我嘗試用字母(例如'noway'或'gg1337')填寫輸入 - 它會生成錯誤並要求輸入有效的數字(不包括例如'13'或'1500000'的字母)C++ cin.clear()和cin.ignore(...)問題
但有一個問題,如果我開始用數字填充輸入,然後添加一些字母(例如'12nowshithappens'),則跳轉到下一個輸入字段,認爲它是有效數字,但顯示。錯誤在一個輸入字段
下面是函數代碼:
int appled()
{
cin >> appleds;
while(cin.fail())
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout << "An arror occured!\nPlease, enter a valid number: ";
cin >> appleds;
}
return appleds;
}
如果我描述了一些錯誤 - 這裏是我的測試程序的完整代碼:)
// exZerry presents
#include <iostream>
#include <conio.h>
int apples;
int fruit;
int oranges;
int x;
int appleds;
int orangeds;
using std::cout;
using std::cin;
using std::endl;
using std::numeric_limits;
using std::streamsize;
char newline = '\n';
bool ok;
bool ok2;
bool ok3;
int appled() //Function to receive 'apples' input
{
cin >> appleds;
while(cin.fail())
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout << "An arror occured!\nPlease, enter a valid number: ";
cin >> appleds;
}
return appleds;
}
int oranged() //Function to receive 'oranges' input
{
cin >> orangeds;
while(cin.fail())
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout << "An arror occured!\nPlease, enter a valid number: ";
cin >> orangeds;
}
return orangeds;
}
int main()
{
ok = ok2 = ok3 = false; //Some testing
while(!ok2) //Actual program loop
{
x = 0; // Dropping program restart.
//cout << "-----------------------" << endl;
//cout << "DEBUG MODE: " << x << endl;
//cout << "-----------------------" << endl;
cout << "=====================================================" << endl;
cout << "Enter apples: ";
apples = appled();
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n'); //Now we have apples
cout << "Enter oranges: ";
apples = oranged();
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n'); //And now we have oranges
cout << "\n=====================================================" << endl;
cout << "Calculating..." << endl;
cout << "=====================================================" << endl;
fruit = apples + oranges;
cout << "In total we have " << fruit << " fruit" << endl;
cout << "=====================================================" << endl;
cout << newline;
//Option to go out or continue the loop
//If you enter 1 - resets the program, any other char - exit
cout << "Go out? (1 - 'No', Others - 'Yeap'):" << " ";
cin >> x;
cout << newline;
// ok2 = true;
if (x == 1)
{
cout << "Continue the program..." << endl;
//cout << "-----------------------" << endl;
//cout << "DEBUG MODE: " << x << endl;
//cout << "-----------------------" << endl;
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
ok = false;
ok3 = false;
continue;
}
if (x == 0)
{
cout << "Shutting down the app..." << x << endl;
//cout << "-----------------------" << endl;
//cout << "DEBUG MODE: " << x << endl;
//cout << "-----------------------" << endl;
break;
}
else
{
cout << "Shutting down the app..." << x << endl;
//cout << "-----------------------" << endl;
//cout << "DEBUG MODE: " << x << endl;
//cout << "-----------------------" << endl;
break;
}
}
cout << "Press any key to exit :D" << endl;
getch();
return 0;
}
'12nowshithappens'基本上被視爲兩個字段,'12'和'nowshithappens'。您還可以輸入多個以空格分隔的數字,如'1 2 3' - 這些將由三個不同的'cin >> some_int_variable'調用愉快地消耗。如果這不是你想要的,使用'getline'將整行讀入'std :: string',然後使用任何你想要的語法解析它。 – 2014-09-10 14:54:21