How to Convert a C++ String to Uppercase

Question

I need to convert a string in C++ to full upper case. I\'ve been searching for a while and found one way to do it:

#include 
#include 

        

Answer 1

#include 

using namespace std;

//function for converting string to upper
string stringToUpper(string oString){
   for(int i = 0; i < oString.length(); i++){
       oString[i] = toupper(oString[i]);
    }
    return oString;
}

int main()
{
    //use the function to convert string. No additional variables needed.
    cout << stringToUpper("Hello world!") << endl;
    return 0;
}