Function call resulting in a strange looping

Hey, all:

I've attached a file here. Basically, it's a program that allows me to test string lengths, copy strings, and compare them(letter-for-letter).

If the 2 comparision string are identical, the program should return a 0, otherwise it should return a 1.

In any case, the situation is that when I enter "R" from my menu, I am taken to my "readString" function where I am prompted to enter a string. This is okay. The problem, however, is that my program doesn't seem capable of escaping the "read" function.

It does something really weird. It keeps asking me for source string based on the number of characters in the first string I enter.

e.g. I enter "the" ( asks me to enter source string 3 more times)
e.g. I enter "them" (asks for a source string 4 more times)

Can someone please check out my attached code and provide me with some feedback?

Thanks!!

Code:

---

int stringLength(char* data)
{
  while(*data)
  {
      strLength++;
  }
  return strLength;
}

---

This doesn't look right. First, you're not increasing the data pointer at each step so you're looking at the first element all the time.
Second, you should compare with \0 (String NULL terminator). I don't know if \0 is the same as 0 (the number) but I'd use \0 anyway.

Code:

---

*sourceString++ = *destinationString++;

---

This is a matter of taste. I prefer not doing several things in the same statement (copy data and increase the pointers). I'd split them to several lines:

Code:

---

*sourceString = *destinationString;
sourceString++;
destinationString++;

---

It's a lot easier to see what happens first(the assignment or the addition).

Code:

---

readData(&data[maxCharacters]);

---

This will point to the character after the last charcacter in the string, which is the NULL terminator, meaning that there is no space to enter a string. Simply call

readData(&data[0]);

or even better

readData(data);

instead

Unfortunately, I still have that weird looping going on in my readData function.

I tried calling readData(&data[0]);
and readData(data);

Neither resolves the issue.

Hmmm.

Well, you don't have your menu selection inside the loop so you will never be promted to enter another option. If you press 'R' the program will ask you to enter strings over and over again.

Thanks a bunch for your help. You're very smart.

My readData now seems to work, but every time I call another of my functions from my menu, my program just exits. Is there something I'm doing wrong in my method calls??

Thanks.