Stringstream

Stringstream 是一个 C++ 标准库中的类，用于将字符串转换为各种数据类型，如整数、浮点数等。它可以将字符串中的数据提取出来，并将其存储到指定的变量中。使用 Stringstream 可以方便地进行字符串和数值之间的转换。

相关问题

stringstream

stringstream is a class in the C++ Standard Library that allows us to treat a string as a stream of characters, which can be read from and written to like any other stream. It provides several methods for converting between strings and other data types, such as integers and floating-point numbers.

The stringstream class is useful for parsing input strings and converting them into different data types, or for constructing output strings from different data types. It is commonly used in situations where we need to manipulate strings and perform operations on them, such as parsing command-line arguments or reading and writing data to files.

To use stringstream, we first include the <sstream> header file. We can then create an instance of the stringstream class, and use its methods to read from or write to the underlying string.

For example, the following code creates a stringstream object and uses it to convert a string to an integer:

#include <iostream>
#include <sstream>

int main() {
    std::string str = "42";
    std::stringstream ss(str);
    int num;
    ss >> num;
    std::cout << "The number is: " << num << std::endl;
    return 0;
}

In this code, we create a stringstream object `ss` initialized with the string `str`. We then use the `>>` operator to extract an integer from the stream and store it in the `num` variable. Finally, we print the value of `num` to the console.

stringstream is a powerful tool that allows us to manipulate strings with ease, and is a valuable addition to any C++ programmer's toolkit.

StringStream

C++中的stringstream是一个流类，它可以将字符串转换为数字、将数字转换为字符串等。stringstream类定义在头文件<sstream>中，使用时需要包含该头文件。

stringstream类的主要用法如下：

1. 将字符串转换为数字

可以使用stringstream类将字符串转换为数字，例如：

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

int main()
{
    string str = "123";
    int num;
    stringstream ss(str);
    ss >> num;
    cout << num << endl;
    return ;
}

输出结果为：

123

2. 将数字转换为字符串

可以使用stringstream类将数字转换为字符串，例如：

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

int main()
{
    int num = 123;
    stringstream ss;
    ss << num;
    string str = ss.str();
    cout << str << endl;
    return ;
}

输出结果为：

123

3. 将多个数据类型转换为字符串

可以使用stringstream类将多个数据类型转换为字符串，例如：

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

int main()
{
    int num = 123;
    double d = 3.14;
    string str = "hello";
    stringstream ss;
    ss << num << " " << d << " " << str;
    string result = ss.str();
    cout << result << endl;
    return ;
}

输出结果为：

123 3.14 hello

以上就是stringstream类的主要用法。