Question about Strings

[incognito]

if I declare a
char ArrayOfChar[50];

And then I do

printf("Enter your Name");
//the user types in John Doe

gets(ArrayOfChar);


This would only be using 9 chars right (one extra one for the null character "\0").....so what happens to the other 41 bytes reserved for chars in this array? Does the computer fill it up with something?

Also how would you set up a for loop to copy everything from one string to the other until it encounter a null character?

this is what I've though of so far

for (int i=0; SourceString[i] !='\0', i++)
DestinationString[i]=SourceString[i];


Please your input on this........

[Stoned_Coder]

dont use gets()
use fgets()

the other 41 chars are assorted garbage that was in there before as the array is uninitialised.

why bother? its already done for you. look up strcpy() in your help files.

[incognito]

I am writing a small program and yes I used fgets

I want to know this because this is what I want to do.....

I am going to ask the Name of a Baseball Player for instance right.........then I am going to create some sort of profile on him with his information, and I want to safe the file as his name......

so if the user types in Babe Ruth........

I want to append .txt to the end of the string so it can be

Babe Ruth.txt.........

I tried doing this........but apparently it doesn't work....

int StringLength;
StringLength=strlen (NameOfFile);
printf("%d", StringLength);
NameOfFile[StringLength];
NameOfFile[StringLength+1]='.';
NameOfFile[StringLength+2]='t';
NameOfFile[StringLength+3]='x';
NameOfFile[StringLength+4]='t';

 Where NameOfFile is "Babe Ruth" or something 

PS Yeah I am a newbie I am just practicing some concepts of C......because I just almost finished reading a book on it.

[Vber]

Probaly it won't work because fgets() leave an '\n' at the end of your string, remove it and use strcat() to add ".txt" to the file.

[Codeplug]

You forgot to terminate the string with a '\0'. Also, NameOfFile[StringLength] == '\0', so you want to start your '.' there.

gg

[Vber]

Maybe you should try something like that:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define EXTENSION ".txt" //the extension we'll add to the file name
int main(void)
{
    char fileName[100]; //the file name we'll get
    
    //get the file name
    printf("Please, enter the file name, without extension\n");
    fgets(fileName,sizeof(fileName),stdin);
    
    //remove \n from the string, and add .txt
    fileName[strlen(fileName)-1] = '\0';
    strcat(fileName,EXTENSION);
    
    //display result
    printf("The full file name: %s\n",fileName);
    system("PAUSE");
    return 0;
}

[incognito]

Thank you people.........I didn't know there was a function as "strcat" :-D

[Prelude]

>fileName[strlen(fileName)-1] = '\0';
Don't forget to test that strlen(fileName)-1 actually is a newline. Otherwise you would be trashing a valid character in the string.

-Prelude

[Vber]

yes Prelude I know that, but I have a question, if in the end of the string we have null, and in strlen-1 we put another null (because we changed the \n to null) this wont give any problem? Whats the better way to remove the \n from the string?

[Hammer]

Originally posted by Vber
yes Prelude I know that, but I have a question, if in the end of the string we have null, and in strlen-1 we put another null (because we changed the \n to null) this wont give any problem? Whats the better way to remove the \n from the string?

No, it won't give a problem. There are various ways to do this, we had a thread about this sometime ago, I'll see if I can find it.

In the meantime:

char *p;
p = strchr(str, '\n');
if (p)  *p = '\0';

[edit]
Here's the earlier thread on this:
http://cboard.cprogramming.com/showt...threadid=24604

[Vber]

Wow! Thanks a lot Hammer and Prelude.