Converting string to char and int data types

Question

I've populated a string vector with with numbers and characters (*,+,-,/). I want to assign each number and character to two new vector, and int vector and a char vector. Is there a way to convert the everything from string to the desired data type?

Answer 1

You can use string stream in the <sstream> header.

string myString = "123";
stringstream sStream( myString );
int convertedInt;
sStream >> convertedInt.

Answer 2

Include the <sstream> header and you can do something like this:

std::vector<std::string> stringVector = /* get data from somewhere */

std::vector<int> intVector;
std::vector<char> charVector;

for (std::vector<std::string>::const_iterator it = stringVector.begin(); it != stringVector.end(); it++)
{
    if (it->length() == 0)
        continue; // ignore any empty strings

    int intValue;
    std::istingstream ss(*it);
    if (ss >> someValue) // try to parse string as integer
        intVector.push_back(someValue); // int parsed successfully
    else
        charVector.pushBack((*it)[0]);
}

This assumes anything that cannot be parsed as an integer should be pushed into the char vector instead (so, 234, 100000 and -34 will be put into intVector, and /, + etc will be put into charVector). Only the first character of a non-integer value is pushed, so if you have *hello or *123, only * will be put into the charVector.

If you are using C++11, you can swap the std::vector<std::string>::const_iterator with auto to make it look a bit nicer.