Thread: Prog Hangs - Something To Do With Pointers

I'm making a substring function. When I call it the prog hangs and I don't understand why Heres my function:

Code:

int String::Sub(char *sub, bool case_sensitive=true)
{
	//Searches for a substring within the string
	//Returns -1 for failure or the index of first occurence
	bool in=false;
	char *a='\0', *b='\0';
	int found=-2; //if returns -2 then somethings wrong

	for(int i=0; i<size; i++)
	{
		a=&str_ptr[i];	
		if(!case_sensitive)
			if(*a >= 'A' && *a <= 'Z') 
				*a+=32;
		
		if(!in)
		{					
			b=sub;
			if(!case_sensitive)
				if(*b >= 'A' && *b <= 'Z') 
					*b+=32;

			if(*a == *b)
			{
				found=i;
				in=true;
			}			
		}
		else
		{
			b++;
			if(*b == '\0') return found;
			
			if(!case_sensitive)
				if(*b >= 'A' && *b <= 'Z') 
					*b+=32;

			if(*a != *b) 
			{	
				in=false;
				i=found+1;
			}
		}
	}
	return -1;
}

If I comment out the red section it works fine, but it won't do a non case sensitive comparison properly. The thing is it works fine for all the other instances where I convert to lower case. Also heres my main function with headers and stuff excluded:

Code:

int _tmain(int argc, _TCHAR* argv[])
{
	String something("Something\n");
	something.Print();
	something.Add("Else\n");
	cout << something.Sub("ELSE", false);
	cin.ignore();
	return 0;
}

Anyone know why this is happening?