C++中的basic_istream :: unget()示例

basic_istream :: unget()用于删除字符，并将位置减少一个字符，并使提取的字符可再次使用。
头文件：

句法：

basic_istream& unget();

参数： basic_istream :: unget()方法不接受任何参数。
返回值：函数basic_istream :: unget()返回basic_istream对象。
下面是说明std :: basic_istream :: unget()的程序：
程序1：

CPP14

// C++ code for basic_istream::unget()
#include 
using namespace std;
  
// Driver code
int main()
{
    // Declare string stream
    istringstream gfg("GeeksforGeeks");
  
    char a = gfg.get();
    if (gfg.unget()) {
        char b = gfg.get();
        cout << "We got: " << a << endl;
        cout << "After ungetting the "
             << "character once again"
             << " we got: "
             << b << endl;
    }
  
    return 0;
}

输出：

We got: G
After ungetting the character once again we got: G

程式2：

CPP14

// C++ code for basic_istream::unget()
#include 
using namespace std;
  
// Driver code
int main()
{
    // Declare string stream
    istringstream gfg("Laptop");
  
    char a = gfg.get();
    if (gfg.unget()) {
        char b = gfg.get();
        cout << "We got: " << a << endl;
        cout << "After ungetting the "
             << "character once again"
             << " we got: "
             << b << endl;
    }
  
    return 0;
}

输出：

We got: L
After ungetting the character once again we got: L

参考： http : //www.cplusplus.com/reference/istream/basic_istream/unget/

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