Problem with sorting a string!!

Hi everyone!
Can any one tell what wrong with this code, I mean when i insert the printf function within the for loop (the i loop) it lists me all the steps correclty. But why it doesn't display the string sorted in one shot using the last printf..that what i want to do..

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 24

int main(){
          char x[SIZE];
          int i, j, t = 0;
          gets(x);
          for (i=1; i<SIZE; i++){
                    t=x[i];
                  for (j = i; j>0 && x[j-1]>t ; j--){
                      x[j]=x[j-1];
                  }
                  x[j]=t;
                  }   
          printf("%s\n",x);
          system("PAUSE");
          return(0);       
}

---

No response??

First of all, if you use gets and the user enters more than twentyfour chars you will get a servere error (probably segmentation fault).

Second of all, the line "int i,j,t = 0" will initate t to 0 while it doesn't initiate i and j, which will make i and j random numbers. I ran the part with the initation and printed out i,j and t and got this output:

i: -1209711522
j: -1209042711
t: 0

Can you say what it's ultimately trying to do? I am having a hard time figuring it out. If I am thinking correctly, I might know how to fix it, but I just need a simple description of what your trying to accomplish.

i, j, and even t don't actually need to be initialised, since they're assigned upon first use.
I would change the type of t to a char though.

The problem is that the outer loop of your insertion sort goes up to i<SIZE, but you didn't necessarily type in SIZE charcters. In fact if you had typed in SIZE characters you'd have a buffer overrun.
Since you're sorting ascending, the null char in the string is being put before the printable chars since it has the lowest value, assuming chars are compiled as unsigned.

Use i<strlen(x) instead in the for loop, or assign strlen(x) to a variable first, and use that.

I'd say it's a bubblesort. I got it working with some changes.

To get the input, I'd do the following. This will avoid getting Segmentation faults, and you will still get the input until the returnchar or the buffer is full:

Code:

---

  int x=0;
  int size=0;

  char* buffer;
  buffer=(char*)malloc(255*sizeof(char)); // or SIZE instead of 255...
  if (buffer==NULL)
  {
      perror("Malloc");
      exit(0);
    }
  ch=getc(stdin);
  while((ch!=10)&&(x<255)) // And SIZE here aswell if you use it above
    {
      buffer[x]=ch;
      ch=getc(stdin);
      x++;
    }
size=x;

---

Quote:

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i and j don't need to be initialised, they're assigned upon first use.

---

I see your point. The strange thing is that I got it working when I initialized i and j. But then again, I counted so I input exactly 24 chars. More than that it won't work, less, I'm not sure.

Quote:

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Originally Posted by Zarniwoop

I'd say it's a bubblesort. I got it working with some changes.

---

You could say that, but you'd be wrong. :) It is Insertion Sort (ascending); I'm not guessing.

Quote:

---

To get the input, I'd do the following. This will avoid getting Segmentation faults, and you will still get the input until the returnchar or the buffer is full:

*** code snipped ***

---

For data input I suggest simply using scanf. Read this

Hi,
I'm sorry for not replying yesterday but i live in morocco, so you may easily figure out that i was sleeping while you were discussing that.
Actually, I'm not allowed to use neither alloc. And yes it is insertion sort...
here is some further implementation, but the problem still persists.
PS: for those how see the thread for the first time, the problem is that the last printf doesn't display the string sorted..why?

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 24

int main(){
          char x[SIZE];
          int i, j,n;
          char t ;
          gets(x);
          for (i=1 , n = strlen(x); i < n ; i++){
                    t=x[i];
                  for (j = i; j>0 && x[j-1]>t ; j--){
                      x[j]=x[j-1];
                  }
                  x[j]=t;
                  }   
          printf("%s\n",x);
          system("PAUSE");
          return(0);

---

works for me

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 24

int main()
{
        char x[SIZE];
        int i, j,n;
        char t ;
        char* end;
        fgets(x,sizeof x,stdin);

        end = strchr(x,'\n');
        if(end) *end = '\0';

        for (i=1 , n = strlen(x); i < n ; i++)
        {
                t=x[i];
                for (j = i; j>0 && x[j-1]>t ; j--)
                {
                        x[j]=x[j-1];
                }
                x[j]=t;
        }   
        printf("&#37;s\n",x);
        return(0);
}

---

result

Code:

---

a;lsdkfjqwpeoriuxlvn
;adefijkllnopqrsuvwx

---

Im not allozed to use any other functions except the ones in my code, normally it sould work, but i just redisplay the string NOT sorted...any comment about my code??

Sorry allowed not allozed

Any??

What do you mean not sorted? Show sample input and output you get?

Ok thanks anybody, Problem solved!!

can anyone help me with this little exercice
Write a program that reads an array of strings, sorts the array using the insertion sort, and displays the sorted array. The array can be declared as follows: char str[SIZE][N]; where N is defined as a preprocessing directive
make sure you use appropriate string functions such as gets to read a string, and strcpy to perform an assignment

First, you show your work, ask your specific questions about problems, THEN we assist.

We're not in the doing homework, business.