Stringstream
时间: 2023-10-23 18:12:15 浏览: 88
Stringstream is a class in C++ that allows you to read and write strings as if they were input/output streams. It is used for converting strings to numerical values, parsing strings, and formatting output. The class is defined in the header file <sstream>. The stringstream class allows you to treat a string as if it were a stream, which means you can use all the standard stream input/output operations on it. This includes inserting data into the string, extracting data from the string, and formatting the string using manipulators. The stringstream class is especially useful when you need to parse a string into individual tokens, or when you need to convert a string into a numerical value.
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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。
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