How can I convert a std string to int

Question

I don't mean ASCII codes when I say I want to convert a string to an int.

For a brief recap, we're given an equation in the form of a string.

We must deconstruct it, accurately format it, and solve the linear equations.

To be clear, I am unable to convert a string to an int.

I know the string will be in the format (-5) or (25) or something similar, so it's definitely an int.

But how do we get that information out of a string?

Running a for/while loop through the text, checking for a digit, extracting all the digits after that, and then looking for a leading '-', if there is, multiplying the int by -1.

Answer 1

There are some new convert methods in C++ that convert std::string to a numeric type.

As an alternative to

str.c str() atoi(str.c str()) atoi(str.c str()

you can make use of

std::stoi std::stoi std::s ( str )

where str is your std::string number.

There are versions for all types of integers, including 

long stol(string), float stof(string), and double stod(string) (string)