I need to figure out how to find the end of a string so I can put a null character '\0' at the end. For example I have this variable:

char phrase[100];

A person enters the phrase: "Hi Mom!"
Thats seven characters. I need to figure out how to put a null character as the eight character, or else I have 92 jibberish characters until it reaches the end of the 100 memory slots. Anybody have any suggestions?

Thanks

How exactly does that phrase get stored in the array? Do you use scanf or cin or something? In that case, it should automatically have the null terminator.

Depends a lot on how you acquire the string. If you are doing scanf("%d", phrase); it will put the null terminator in there for you. If you're getting a character at a time until they hit the return key, and you have the length stored in a variable, it's pretty easy.

prase[length] = '\0';

doh. You wouldn't do scanf("%d", phrase); Maybe scanf("%s\n", prase);

I planned on getchar(). scanf() only gets characters up to a space. So if somebody typed "Hi Mom!", scanf() would just capture "Hi". Explain how to get the length of the characters typed. Also I thought about saying:

char phrase[100];

while (i less_than phrase) {
phrase[i];
i++;
}

Or something to that extent, but that seems like a little much. Explain how to get the length of the characters typed.
Thanks

Right, so you're using a loop. Well, like Jim said, you can use a variable (i) to count how many times you call getchar(). You could then simply:
phrase[i] = '\0';
i is incremented everytime the loop is executed, and getchar is called once everytime the loop is executed, so i should be the length of the string.
(i, as in the variable, i. I am not the length of the string) =P

yeah, if you use getchar(), just increment a counter whenever it gets anything other then an enter.

but if you ask me, i would probably reset the array before i use it (cycle through from 0 to n, and put the null character in each position). from a performance standpoint, it might be bad, but in my classes, performance doesn't matter...

I don't understand what hmmm said, but I do understand the looping and counting. Thats not a bad way to do it.

Hmm was pointing out that if you fill the array with zeros before you start, there won't be any need to put one on the end. There will already be one there. As well as in every space after that, but that's kinda irrelevant.

There's probably a function to fill the array with zeros. Check your documentation for things like setmem() or memset().

As Jim says, set the array to 0

#define PHRASE_MAX 100
char phrase[PHRASE_MAX];
memset (phrase, '\0', PHRASE_MAX);

/* Get the input line */
gets (phrase);

Or if you prefer C++/STL

string phrase;
getline (cin, phrase);

Neat way of doing that. Something I hadn't thought of. Does anybody know which way is faster and or more stable.

The C method is faster but it has one problem: if the string is more than 99 chars, it will crash.

The C++ method is more stable but, if you are using VC++, use you'll hit a bug where you have to input the first line twice. Unfortunately, to get around it, you're back to the C method. If you are not using VC++, it is not a problem.

char phrasec[PHRASE_MAX];
cin.getline (phrasec, PHRASE_MAX);
string phrase (phrasec);

char *ptr;
char phrase[100];

ptr = phrase;

while((*ptr++ = getchar())!='\n') /*empty loop*/ ;

*--ptr = '\0';

Or something like that... haven't compiled it so please excuse syntax errors. As an engineer who spends most of his time optimising code for size/performance, the "fill the array with zeros" option brought me out in a cold sweat :) also... pointers are generally more efficient than indexing into an array.

Of course... an array limit check could also be included in the loop condition.