Thread: Reversing String Problem

Hi
I'm learning to script in C and i've noticed it's not as simple as i want it to be...

I am following the Emulov website to start learning c and in chapter 3 he tells me to make a program that has to have an input of your first and last name. each separately given in a separate string. Then he asks me to put the strings behind each other in the output and when it has done that it also has to put the strings in reverse behind each other.

I've tried to make it work.. but when the inputnames are too long it cut's them off. and with the last name the program has no problem but with the first name it gives a bunch of crap in front of the name..

it's really annoying me and when i look up the sollution on google.. the answers are all too advanced for me to understand..:/

i'm just learning about arrays and multidimensional arrays.. don't know how to work with pointers or little parts of programming defined in the same program..


my program is as follows(also an attachment to be sure):

Code:

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

int main(void){
    char content, inhoud2;
    char naam[0], voor[0];
    int length=strlen(naam)-1, lengte=strlen(voor)-1;
    
    printf("Geef uw voornaam in: ");
    scanf("%s",voor);
    printf("Geef uw naam in: ");
    scanf("%s",naam);
    
    printf("U bent dus %s %s\n\n", voor, naam);
    
     printf("In omgekeerde volgorde is dat:");
    for(inhoud2=length;inhoud2>-1;inhoud2--){
     printf("%c", naam[inhoud2]);}
     printf("\n");
    for(content=lengte+1;content>-1;content--){
     printf("%c", voor[content]);} 
   
   
    
getch();

}

i'm sorry about the dutch words but it shouldn't matter to the advanced scripters among us...

already thx and hoping to hear something soon...

If your tutorial book/site has this line
char naam[0], voor[0];
It's time to leave it behind...
I'd recommend The C programming Language, The C Book,...
Btw, C is not a scripting language...

i already have the book: the C programming language.
but since it is written in english and somethings not explained well enough.. i sought out an other tool.


char naam[0], voor[0]; is something i have written.. it doesn't give examples on how to make that program ... it tells you what the kinds of arrays and strings are and then you have to make your own program... (that's just for now...) it's only chapter three u see..

and sorry.. didn't know there being a difference in scripting and programming...

I think you are using gcc compiler?
Array of size 0 is strictly speaking, wrong and compiler should give you error.
But gcc by default uses gcc C. not standard C.
So always use gcc -std=c89 -Wall -pedantic-errors source.c to compile your source file.

i'm not using gcc compiler. although not that i know of.
i'm using dev-c++ as a typing aid so i'm using that compiler too.

Originally Posted by Bennie98

Code:

    char content, inhoud2;
    char naam[0], voor[0];

You need to give these buffers a pre-set size... Perhaps 50 characters or so, to allow room for the longest name you're likely to encounter.

Code:

char naam[50];
char voor[50];

omg you can screw your system up by trying something ? ^^ very safe programming then

and no it hasn't done that.... but it spewed out a whole rant of figures and symbols...

and i read somewhere that you have to subtract 1 because of the first memory allocation which is always 0 in an array...

but i'll change the things you said and i hope it's going to work

i tried it... i changed the buffer to 250 and i deleted the minus 1

now it still clips but now it shows only 4 characters in last name and 2 characters in first name...

Originally Posted by Bennie98

omg you can screw your system up by trying something ? ^^ very safe programming then

I've had to reformat and reinstall after some of my more disastrous experiments... so yes, this dog really can eat your homework.

and no it hasn't done that.... but it spewed out a whole rant of figures and symbols...

Because you were working in unallocated memory.

and i read somewhere that you have to subtract 1 because of the first memory allocation which is always 0 in an array...

I think you are confusing the number of elements with the number of the element. A C array of 10 items has items numbered 0 to 9 ...

but i'll change the things you said and i hope it's going to work

Can it get any worse?

Code:

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

int main(void){
    char content, inhoud2;
    char naam[0], voor[0];
    int length, i;
    
    printf("Geef uw voornaam in: ");
    scanf("%s",voor);
    printf("Geef uw naam in: ");
    scanf("%s",naam);
    
    length=strlen(naam); 
    lengte=strlen(voor); //moved -1's removed, replaced comma with semi-colon
    printf("U bent dus %s %s\n\n", voor, naam);

    
     printf("In omgekeerde volgorde is dat:");

    //what you're printing are char's, but the index counter i is an int
    for(i=length;i>-1;i--) {
       printf("%c", naam[i]);  //indent subordinate code lines
    } //closing braces go right below the first char that started them - 'f' in this case
     printf("\n");
    for(i=lengte;i>-1;i--) {
       printf("%c", voor[content]);
    } 
    getch();

}