Need assistance with Pointer

[shanex88]

Hi, I had just started learning pointer and my lecturer want me to use pointer for my assignment.

basically I have to use pointer and its arithmetic to do it and not allowed to use
Eg. key[k]/ *(key+k) to access the k^th element.

I have the code:

	char *pKey = &key[0];
				
	//int i = 0;
	//while ( i < strlen(pKey))
	  
        while ( *pKey != '\0')
	{
		
		*pKey = (char)tolower(*pKey);
		pKey++;
		
	//pKey[i] = (char)tolower(pKey[i]);
	//i++;
		
	}	 
	        cout << "pKey is: " << pKey;

as you can see I had replaced the commented statement with pointer way to convert the pointer array to lower case. The prob is when I cout the pKey,
it is empty.

Can anyone help identify the problem? thank you!

[hamsterman]

That's because if in the beginning pKey pointed to hello\0, after one ++ it will point to ello\0 and after the whole loop it will point just to \0. You need to make a copy of pKey pointer and do the operations with that copy. Then when you want to print pKey it will still point to the same place.

[shanex88]

ahh didnt know it work this way. now it works, thanks!