How to convert a string to an int using std?

We can also use the std::atoi function to convert a string to an int. It takes a C-string as a parameter, so we need to convert our string to a C-string. We can do that using std::string::c_str. Please note that its behavior is undefined if the converted value is out of the range of integer data type.

How do I convert a string to an integer?

return i; atoi is a built-in function that converts a string to an integer, assuming that the string begins with an integer representation. Any time you think about atoi, use strtol instead. Both atoi and strtol return 0 when no conversion is possible. So there's still validation required before using it.

How to convert string representation to integer value using std?

To convert from string representation to integer value, we can use std::stringstream. if the value converted is out of range for integer data type, it returns INT_MIN or INT_MAX. Also if the string value can’t be represented as an valid int data type, then 0 is returned. std::string x = "50"; int y;