处理空格字符作为输入

Question

#include <iostream> 
using namespace std; 

int main() { 
    int x; 
    char y; 
    cin >> x; 
    while(!cin) 
    { 
     cout << "Error" << endl; 
     cout << "Enter x and y again => "; 
     cin.clear(); 
     cin.ignore(256,'\n'); 
     cin >> x; 
    } 
    cin >> y; 
    while (!(!isblank(y) && isalpha(y))) 
    { 
     cout << "You have entered wrong values try again!" << endl; 
     cout << "Enter x and y again => "; 
     cin >> x >> y; 
    } 
    return 0; 
} 

我试着处理，如果输入的输入是1 a。 x应该是一个数字y也应该是字母字符。它应该再次要求输入值x和y。但是，它没有。它应该接受1a。如何克服这个问题？

Answer 1

我会一次读取一行到缓冲区并使用stringstream从该缓冲区读取。下面是我的什么作品：

int x; 
char y; 
bool readin_successful = false; 
while (cin) { 
    cout << "Please enter x and y => "; 
    char z; 
    string buffer; 
    getline(cin, buffer); 
    stringstream bin(buffer); 
    bin >> x >> y; 
    bool const first_ok = (isalpha(y) and bin.good()); 
    bin >> z; 
    if (first_ok and not bin.good()) { 
     readin_successful = true; 
     break; 
    } 
    cout << "You have entered wrong values try again!" << endl; 
} 
cout << "Read: " << x << " " << y << " " << readin_successful << endl; 

它同时接受0 x和0x，而不是别的什么（忽略空格）。 Here是我测试过的示例输入。

Answer 2

我找到了解决方案。 std::noskipws表示不跳过空格。

#include <iostream> 
using namespace std; 

int main() { 
    int x; 
    char y; 
    cin >> x; 
    while(!cin) 
    { 
     cout << "Error" << endl; 
     cout << "Enter x and y again => "; 
     cin.clear(); 
     cin.ignore(256,'\n'); 
     cin >> x; 
    } 
    cin >> noskipws >> y; 
    while (!(!isblank(y) && isalpha(y))) 
    { 
     cout << "You have entered wrong values try again!" << endl; 
     cout << "Enter x and y again => "; 
     cin.clear(); 
     cin.ignore(256,'\n'); 
     cin >> x >> y; 
    } 
    return 0; 
}