How To: STL String Case-insensitive Compare

This article is talking about how to do a case-insensitive compare for STL string and wstring, there're 2 ways to reach the goal.

Method #1: C Run-time Library - _stricmp() and _wcsicmp()

#include <string>

using namespace std;

string strUpperCase = "ABC";
string strLowerCase = "abc";
if(_stricmp(strUpperCase.c_str(), strLowerCase.c_str()) == 0)
// For wstring, use _wcsicmp() instead.
{
  // Do something you need
}

Method #2: STL Algorithm - transform()

#include <cctype>
#include <string>
#include <algorithm>

using namespace std;

// I make a helper function to compare string
bool CompareCaseInsensitive(string strFirst, string strSecond)
{
  // Convert both strings to upper case by transfrom() before compare.
  transform(strFirst.begin(), strFirst.end(), strFirst.begin(), toupper);
  transform(strSecond.begin(), strSecond.end(), strSecond.begin(), toupper);
  if(strFirst == strSecond) return true; else return false;
}

string strUpperCase = "ABC";
string strLowerCase = "abc";
if(CompareCaseInsensitive(strUpperCase, strLowerCase))
{
  // Do something you need
}

Reference in This Site:
How to convert STL string / wstring to upper / lower case?

Reference in MSDN:
_stricmp, _wcsicmp, _mbsicmp, _stricmp_l, _wcsicmp_l, _mbsicmp_l