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Questions tagged [istringstream]

Anything related to C++ `istringstream` standard library class. This class represents an "input string stream", i.e. an input stream that allows a string to be used as the source of information attached to the stream.

Anything related to C++ istringstream standard library class. This class represents an input string stream, i.e. an input stream that allows a string to be used as the source of information attached to the stream.

istringstream is a specialization of the basic_istringstream template class and it is defined in C++ <sstream> standard library header.

See CPPreference.com on basic_istringstream template class.

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Why does string_stream.str() = a_string; compile?

I can create an std::istringstream like so std::istringstream string_stream(inp_string); I can then change the contents of the stream: string_stream.str(std::move(inp_string_2)); However, I might accidentally try something like…
user589321
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Reading string by string in a file's lines using a for loop in C++

I need help with my C++ code, which reads data from an ASCII file and stores them into an std::vector. The data are stored consecutively (as in the example below). For some reasons I want to substitute the while(iss>>token) with a for loop,…
fslack
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Extraction operator into non-numeric character

Given an istringstream, is it possible to "extract" its contents into a character only if the character to be extracted is non-numeric (i.e. not 0-9)? For example, this string foo = "+ 2 3"; istringstream iss(foo); char c; iss >> skipws >> c; …
Anakhand
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Redirect C stdin to read from C++ stringstream

I have some code that was provided to me written in C that I'm using in a C++ project. I need to add some functionality, along with unit tests. Unfortunately it's hard coded to use getchar and other C IO functions in a way that isn't very easy to…
anderspitman
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istringstream ignores first letter

I am trying to access different words in a string using std::istringstream and I am also doing so with multiple test cases. int t; cin>>t; while(t--) { string arr; cin.ignore(); getline(cin,arr); istringstream iss(arr); …
amora
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Reading a double from an istream in Hex

Given double foo I can assign it from a hex format string using sscanf like this: sscanf("0XD", "%lg", &foo) But I cannot seem to get an istringstream to behave the same way. All of these just write 0 to foo: istringstream("0XD") >>…
Jonathan Mee
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Cast string object to istringstream

#include #include #include #include #include void reverse_words(const std::string &file) { std::ifstream inFile { file }; std::vector lines; if(static_cast(inFile))…
Gabriella Lenzi
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std::getline skipping input from std::cin after last occurrence of delimiter, but not with input from std::istringstream

I need to read some input that is delimited by a whitespace, the main construction I used for this is: while(std::getline(std::cin, s, ' ')){ std::cout << s << std::endl; } For the input: "this is some text" The output for S will be: "this",…
HansKlokkenspel
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Extracting bool from istream in a templated function

I'm converting my fields class read functions into one template function. I have field classes for int, unsigned int, long, and unsigned long. These all use the same method for extracting a value from an istringstream (only the types change): …
Thomas Matthews
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Convert string to __uint128_t using stringstreams

I'm trying to extract different types of data from a string. void readHeader(char buf[BUFFSIZE]) { std::istringstream hdr(buf); __uint128_t id_client; hdr >> id_client; // doesn't compile } I'm getting this…
Amina
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How to save and restore an std::istringstream's buffer?

I am using a istringstream to read a string word by word. However, when my condition fails I need to be able to revert the istringstream to before the previous word was read. My example code works, but I want to know if there is a more direct way…
user870130
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Passing temporary istringstream object to istream_iterator

I have a question about the following code that tokenizes a string (separates the tokens by space). #include #include #include #include #include using namespace std; int main() { string s="And…
vsoftco
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C++ Adapting sscanf code to istringstream with error checking

So I've got some code that splits a string into some other variables with sscanf that looks like this. if(sscanf(input_line.c_str(), "%s %s %lf %lf %lf", &string1, &string2, &point1, &point2, &point3) != 5) { //does stuff throw; } I use…
Max Rahm
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How to convert istringstream object to string and char array?

I have this object: istringstream ob_stream; I need to convert this object to string and char array for work. How to do?
user1779502
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Obtaining start position of istringstream token

Is there a way to find the start position of tokens extracted by istringstream::operator >>? For example, my current failed attempt at checking tellg() (run online): string test = " first \" in \\\"quotes \" last"; istringstream…
Jason C
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