Trim function

[Prabu Ramasamy]

here i kno trim function wil remove first and last whitespaces if occured. but i don the program for that.string wil u pleas explain this program step by step?
particularly why they take the concept of takin condition >' ' in conditional statement.
program: i didnt send main,class definition simply function definition

          string StringUtil::Trim(string givenString)
{
     int count = givenString.length();
     if (count == 0 || (givenString[0] > ' ' && givenString[count-1] > ' '))
         return givenString;
 
    int preTrim = 0;
    for (;; preTrim++)
    {
         if (preTrim == count)
             return givenString;
        if (givenString[preTrim] > ' ')
            break;
    }
    int endTrim = count;
     while (givenString[endTrim-1] <= ' ')
        endTrim--;
     return this->SubString(givenString, preTrim, endTrim-1);
};

[weaknessforcats]

OK. Here you go:

[code=cpp]
string StringUtil::Trim(string givenString)
{
//
//This is a deprecated method. You should use givenString.size().
//None of the other STL containers have a length() but all have a size().
//
// VVVVVVVVVVVVVVVVV
int count = givenString.length();
//
//So, if the count is zero there oare no characters in the string.
//There's nothing to trim and the function returns.
//OR
//look at both ends of the string. If there's nothing to trim, the function returns.
//This is done with an expression that says
//if the first character of the string is greater than a space
//AND if the last charaacter is greater then a space, then there's
//nothing to trim and the function returns.
//
//Refer to the ASCII table. You will see that all non-space characters
//are greater than the value of a ' ' (which is 48 by the way).
//
if (count == 0 || (givenString[0] > ' ' && givenString[count-1] > ' '))
return givenString;
//
//This section skips over all leading spaces (if any).
//
// VVVVVVVVVVVVVVV
int preTrim = 0;
for (;; preTrim++)
{
if (preTrim == count)
return givenString;
if (givenString[preTrim] > ' ')
break;
}
//
//This section skips over the trailing spaces.
//
// VVVVVVVVVVVVVVVVVVVVV
int endTrim = count;
while (givenString[endTrim-1] <= ' ')
endTrim--;
//
//Finally, copy from the first non-space through the last non-space
//and put eh copy back into the original string.
//
//VVVVVVVVVVVVVVVVVVVVVVVVVV
return this->SubString(givenString, preTrim, endTrim-1);
};
]/code]