Converting String to Float/Double
1. Using std::stof() and std::stod() function
stof() function takes a string object as an input and returns the floating point number corresponding to that string as an output. On the other hand stod() takes a string as input and returns double data type as an output.
Syntax:
float variable_name = std::stof(string_name); double variable_name = std::stod(string_name);
Example:
C++
// C++ program to convert // string into float/double #include<bits/stdc++.h> using namespace std; int main() { // Initializing the string string str = "678.1234"; // Converting string to float float str_float = std::stof(str); // Converting string to double double str_double = std::stod(str); cout<< "string as float = " << str_float << endl; cout<< "string as double = " << str_double << endl; return 0; } |
Output
string as float = 678.123 string as double = 678.123
2. Using std::atof() function
In C++ the character array can be converted to any numeric data type like float/double using the help of atof() function. This function takes a string as a parameter and returns float/double as output.
Syntax:
float variable_name = std::atof(string_name); double variable_name = std::atof(string_name);
Example:
C++
// C++ program to convert // float/double into string #include<bits/stdc++.h> using namespace std; int main() { // Initializing the char array char str[] = "678.1234"; // Converting char array to float float str_float = std::atof(str); // Converting char array to double double str_double = std::atof(str); cout<< "char array as float = " << str_float << endl; cout<< "char array as double = " << str_double << endl; return 0; } |
C++ String to Float/Double and Vice-Versa
In this article, we will learn how to convert String To Float/Double And Vice-Versa. In order to do conversion we will be using the following C++ functions:
- std::stof() – convert string to float
- std::stod() – convert string to double
- std::atof() – convert a char array to double
- std::to_string – convert any data type number to string
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