Thread: Very simple clarification about strings (I hope).

Originally Posted by figarojones

I'm currently taking an online C-programming class, and one of the things that was taught to remove a '\n' from a string, was to use the line

Code:

 str [lenOfStr - 1] = '\0';

I get that the '-1' removes the the '\n', but was wondering why the '= '\0'' is necessary. I thought all empty segments after the string automatically filled with the null digit, so I'm curious why it doesn't in this case.

The code you posted sets the last character to value 0 or ASCII nul; this is with the assumption that lenOfStr contains the length of the string before the operation.
The length of the C-string is 1 character shorter after that line is done.

Tim S.

Nothing much "fills automatically" with C. YOU do the filling, unless you specifically call a function (like calloc() or memset(), that will fill it for you). When a string is first set, using scanf() (and that "family" of input functions, or something like fgets() or

Code:

char str[]={"That's where I come from"};

Then C will add the end of string char for you. Likewise string functions will all do it, but they work with strings already created for the most part.

A bunch of letters or digits are just that - a bunch. They do not constitute a string. A string in C MUST have a zero or null char ( '\0') at the end of it. THEN it's a string.

It's good to put the above as the second line of an if(str[lenOfStr-1]=='\n') statement, so you know you'll be overwriting only when there is an \n in there.