std :: istringstream是一个字符串类对象，该对象用于将字符串流式传输到不同的变量中，并且类似地，文件也可以流式转换为字符串 。此类的对象使用包含字符序列的字符串缓冲区。可以将这个字符序列作为字符串对象进行访问。
头文件：
#include
1.使用std :: istringstream从字符串流式传输整数
一种流字符串是使用来自标题的输入字符串流对象std :: istringstream 。一旦创建了std :: istringstream对象，就可以使用提取运算符( >> )对字符串进行流传输和存储。提取运算符将读取直到达到空格或流失败为止。
下面是std :: istringstream的说明：
// C++ program to illustrate std::istringstream
#include
#include
#include
using std::istringstream;
using std::string;
using std::cout;
// Driver Code
int main()
{
// Input string
string a("1 2 3");
// Object class of istringstream
istringstream my_stream(a);
// Variable to store number n
int n;
// Stream a number till white space
// is encountered
my_stream >> n;
// Print the number
cout << n << "\n";
}
输出：
1
std :: istringstream对象也可以用作布尔值，以确定上一次提取操作是否失败。如果流中没有更多的字符串，则会发生这种情况，例如，如果流中仍有更多字符，则我们可以再次流传输该字符串。
提取运算符>>的流写入到在运算符和返回的std :: istringstream对象的右侧变量，所以整个表达my_stream >> n是一个std :: istringstream对象，它返回一个布尔值，即，如果真流否则可能返回false。
以下是通过上述方式使用std :: istringstream的实现：
Type 1
// C++ program to illustrate std::istringstream
#include
#include
#include
using std::istringstream;
using std::string;
using std::cout;
// Driver Code
int main()
{
// Input string
string a("1 2 3");
// Object class of istringstream
istringstream my_stream(a);
// Variable to store number n
int n;
// Testing to see if the stream was
// successful and printing results.
while (my_stream) {
// Streaming untill space is
// encountered
my_stream >> n;
// If my_stream is not empty
if (my_stream) {
cout << "That stream was successful: "
<< n << "\n";
}
// Else print not successful
else {
cout << "That stream was NOT successful!"
<< "\n";
}
}
return 0;
} Type 2
// C++ program to illustrate std::istringstream
#include
#include
#include
using std::istringstream;
using std::string;
using std::cout;
// Driver Code
int main()
{
// Input string
string a("1 2 3");
// Object class of istringstream
istringstream my_stream(a);
// Variable to store number n
int n;
// Testing to see if the stream was
// successful and printing results.
while (my_stream >> n) {
cout << "That stream was successful: "
<< n << "\n";
}
cout << "That stream was NOT successful!"
<< "\n";
return 0;
} 输出：
That stream was successful: 1
That stream was successful: 2
That stream was successful: 3
That stream was NOT successful!
2.混合类型的字符串
在上面的插图中，字符串仅包含可以转换为int的空格和字符。如果字符串具有混合类型，即在流中包含多个数据类型，则可以按如下所示使用它。
下面是混合类型的std :: istringstream的说明：
程序1：
// C++ program to illustrate std::istringstream
// when string has integer followed by character
#include
#include
#include
using std::istringstream;
using std::string;
using std::cout;
// Driver Code
int main()
{
// Input string
string str("1, 2, 3");
// Object class of istringstream
istringstream my_stream(str);
// Variable to store the number n
// and character ch
char c;
int n;
// Traverse till input stream is valid
while (my_stream >> n >> c) {
cout << "That stream was successful: "
<< n << " " << c << "\n";
}
cout << "The stream has failed."
<< "\n";
return 0;
}
输出：
That stream was successful: 1,
That stream was successful: 2,
The stream has failed.
程式2：
// C++ program to illustrate std::istringstream
// to tokenize the string
#include
#include
#include
using std::istringstream;
using std::string;
using std::cout;
// Driver Code
int main()
{
// Input string
string str("abc, def, ghi");
// Object class of istringstream
istringstream my_stream(str);
// To store the stream string
string token;
size_t pos = -1;
// Traverse till stream is valid
while (my_stream >> token) {
// If ',' is found then tokenize
// the string token
while ((pos = token.rfind(','))
!= std::string::npos) {
token.erase(pos, 1);
}
// Print the tokenize string
cout << token << '\n';
}
}
输出：
abc
def
ghi
参考： http : //www.cplusplus.com/reference/sstream/istringstream/
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