How to Read File into String in C++? Last Updated : 21 May, 2024 Comments Improve Suggest changes Like Article Like Report In C++, file handling allows us to read and write data to an external file from our program. In this article, we will learn how to read a file into a string in C++. Reading Whole File into a C++ StringTo read an entire file line by line and save it into std::string, we can use std::ifstream class to create an input file stream for reading from the specified file with a combination of std::getline to extract the lines from the file content that can be concatenated and stored in a string variable. ApproachOpen the file using std::ifstream file(filePath).Use the is_open() method to check if the file was opened successfully, if not print error message and return.Use a loop with std::getline(file, line) to read each line of the file into a string and print the populated string.Close the file stream.C++ Program to Read a File into StringThe below program demonstrates how we can read the content of a file into a std::string line by line in C++. C++ // C++ Program to demonstrate how to Read a File into String #include <fstream> #include <iostream> #include <string> using namespace std; int main() { // get the filepath string filePath = "myFile.txt"; // Open the file using ifstream ifstream file(filePath); // confirm file opening if (!file.is_open()) { // print error message and return cerr << "Failed to open file: " << filePath << endl; return 1; } // Read the file line by line into a string string line; while (getline(file, line)) { cout << line << endl; } // Close the file file.close(); return 0; } Output File Content: Hi, Geek! Welcome to gfg. Happy Coding ;)Time Complexity: O(n), here n is total number of characters in the file.Auxiliary Space: O(n) Comment More infoAdvertise with us Next Article How to Read File into String in C++? S sonijaiog3d Follow Improve Article Tags : C++ Programs C++ cpp-file-handling C++ File Programs CPP Examples +1 More Practice Tags : CPP Similar Reads How to input a comma separated string in C++? Given an input string which is comma-separated instead of space, the task is to parse this input string in C++.First, let us understand what difference does it create if the input string is comma-separated. Taking input a whitespace-separated stringTaking input a whitespace-separated string in C++ i 2 min read How to Read Input Until EOF in C++? In C++, EOF stands for End Of File, and reading till EOF (end of file) means reading input until it reaches the end i.e. end of file. In this article, we will discuss how to read the input till the EOF in C++. Read File Till EOF in C++The getline() function can be used to read a line in C++. We can 2 min read How to Read a File Line by Line in C++? In C++, we can read the data of the file for different purposes such as processing text-based data, configuration files, or log files. In this article, we'll learn how to read a file line by line in C++. Read a File Line by Line in C++We can use the std::getline() function to read the input line by 2 min read How to Read a File Using ifstream in C++? In C++, we can read the contents of the file by using the ifstream object to that file. ifstream stands for input file stream which is a class that provides the facility to create an input from to some particular file. In this article, we will learn how to read a file line by line through the ifstre 2 min read How to Read From a File in C++? Reading from a file means retrieving the data stored inside a file. C++ file handling allows us to read different files from our C programs. This data can be taken as input and stored in the program for processing. Generally, files can be classified in two types:Text File: Files that contains data i 4 min read How to Match a Pattern in a String in C++? In C++, strings are sequences of characters stored in a char array. Matching a pattern in a string involves searching for a specific sequence of characters (the pattern) within a given string. In this article, we will learn how to match a pattern in a string in C++. Example: Input:Text: "GeeksForGee 2 min read How to Read a Line of Input Text in C++? In C++, we often need to take input from the user by reading an input text line by line but the cin method only takes input till whilespace. In this article, we will look at how to read a full line of input in C++. For Example, Input: This is a text.Output: Entered Text: This is a text.Taking a Line 2 min read How to Split a String into an Array in C++? In C++, splitting a string into an array of substrings means we have to parse the given string based on a delimiter and store each substring in an array. In this article, we will learn how to split a string into an array of substrings in C++. Example: Input: str= âHello, I am Geek from geeksforgeeks 2 min read How to Handle Multiple String Inputs with Spaces in C++? In C++, strings are a sequence of characters that might contain spaces in many cases but we can read only the input text till whitespace using cin. In this article, we will learn how to handle multiple string inputs with spaces in C++. Example: Input:Enter multiple strings:String1String2Output:You E 2 min read How to Split a String by a Delimiter in C++? Splitting a string is the process of dividing the given string into multiple substrings on the basis of a character (or substring) as the separator. This separator is called delimiter and the whole process is also called tokenization.ExamplesInput: str = "geeks,for,geeks", delimiter = (,)Output: gee 4 min read Like