array problem

vaha · #1 14-May-2005, 17:20

Hi all, im new in C world and I need your's help for one simple prog.
Program: enter array like this A=(1,2,3,4,5,6) (number of elements n=6) you need to delete one element (z=4) from that A array and print A array like A=(1,2,3,5).

((sorry for bad english))

WaltP · #2 14-May-2005, 21:47

Welcome to GID vaha....

So what's the problem you're having? Understanding the problem? Designing the solution? Coding the solution? Compiler arrors? Runtime errors? Logic errors?

Read the Guidelines for posting requests for help so you understand what we need to help you solve your task.

ajitham · #3 15-May-2005, 03:21

Hello vaha,

As a new programmer you may have this sort of problems.Even i'm new to programming even i'm having this sort of problems.

OK the problem you've got is very simple actually.Insert the following in your program to get u the result.

CPP / C++ / C Code:


//first input the array.

int position;    //input the position where you would like the deletion
int k;             //some value to represent the array element
int i;               //to loop through

k=position;

for(i=6;i>=position;i--)         //since your array length is 6
{
         a[k]=a[k+1];                   //move your array elements
         k++;
}

this is very simple is it not.Now you try yourself to insert an element at the desired position. Somewhat similar to this, but different.

vaha · #4 15-May-2005, 07:50

i had problem when user enters all same numbers for array elemenets and want one to remove, and when element that user wants out of array is last one. no new array is alowed to use.
here is my raw code sample:

CPP / C++ / C Code:

#include<stdio.h>
#include<conio.h>
#define MAX_NIZ 30

int i,n,z,a[MAX_NIZ];
char answer;

void main()
{
 for(i=0;i<MAX_NIZ;i++) a[i]=0;
 textcolor(12);
do
{

 do
   {
clrscr();
printf("\n\t\t Number of elements for array X:");
scanf("%d",&n);
printf("\n\t\t Enter elementsX:\n");
   }
   while(n<1 || n>MAX_NIZ );
   for(i=0;i<n;i++){
    printf("\t\t");
    scanf("%d",&a[i]);}

    printf("\n\t\t Enter elemnt for removing");

    scanf("%d",&z);

 clrscr();
 printf("\n\t\t Number of elements for array X n= %d.",n);
 printf("\n\t\t Enter elements X:");
 printf("\n\t\t");
for(i=0;i<n;i++)
 {
  textcolor(15);
  cprintf(" %d ",a[i]);}
  textbackground(7);
  textcolor(16);
  printf("\n");

for(i=0;i<n;i++)
 {
 if(a[i]==z) a[i]=a[i++];   // there is problem ---- works when i remove one elemet (not last one) 
 printf("\n\t\t %d",a[i]);  // when i enter last element to remove i get 0, when i enter to remove duplicate elements program  dont work
 }



  printf("\n\n\n\t\t\t Do you want to continue (Y/N)");
	  flushall();
	  scanf("%c",&answer);
}
	 while (answer == 'y' || answer=='Y');


 gotoxy(1,25);

 }

and one more qest. , how can i prevent users to enter letters for elements?
when i enter program crash, is ther any way to do that with standard lib -stdio.h-?

WaltP · #5 15-May-2005, 11:03

Your problems seems to be here:

CPP / C++ / C Code:

for(i=0;i<n;i++)
{
    if(a[i]==z) a[i]=a[i++];   // there is problem 
    printf("\n\t\t %d",a[i]);  // when i enter last 
}

All this loop does is find each value z and replace it with the next value in the array. So if you have
1 4 5 8 9 and z is 5 you end up with
1 4 8 8 9 in the array.

What you need to do to remove z is

Code:

n = number of values
loop thru array from 0 to n-1  
    if a[index] = z then
        if index < n-1 then
            loop thru array from index to n-2 moving a[index2+1] int a[index2]
        endif
        decrement n
    endif
endloop

You can't use a for loop for the first loop because your endpoint keeps moving.

Quote:

Originally Posted by vaha

and one more qest. , how can i prevent users to enter letters for elements?
when i enter program crash, is ther any way to do that with standard lib -stdio.h-?

Stand over the user with a baseball bat ready to swing.....

Not easily. This takes a completely different form of input than you probably can do at the moment. After a few more weeks of class this will be easier.

Also read this tutorial on how to format your code. Your formatting make the code difficult to read because it is inconsistant.

vaha · #6 15-May-2005, 17:02

Thanks WaltP,

Quote:

Originally Posted by WaltP

Your problems seems to be here:

CPP / C++ / C Code:

for(i=0;i<n;i++)
{
    if(a[i]==z) a[i]=a[i++];   // there is problem 
    printf("\n\t\t %d",a[i]);  // when i enter last 
}

All this loop does is find each value z and replace it with the next value in the array. So if you have
1 4 5 8 9 and z is 5 you end up with
1 4 8 8 9 in the array.

no, that loop do this:
if i have 1.4.5.8.9 and z= 4
i get 1.5.8.9
But when i set z=9 result= 1.4.5.8.0
and if i have 2.4.4.6.7 i can't use this loop for z=4.

Quote:

Code:


n = number of values
loop thru array from 0 to n-1  
    if a[index] = z then
        if index < n-1 then
            loop thru array from index to n-2 moving a[index2+1] int a[index2]
        endif
        decrement n
    endif
endloop

this is :

CPP / C++ / C Code:

for (i=0 ; i<n-1; i++)
 {
   if (a[i] == z)
     {
       if (i < (n-1) )
            {
               for (i=0; i < (n-2) ; i++)
                   {
                     a[j+1] == a[j];
                     j++;

                   }
             }

        n=j;
     }


  }

corect me if im wrong.

ubergeek · #7 15-May-2005, 17:17

the only problems are in your for loop conditions (I don't know if that will work, by "problem" i mean "different than the psuedocode")

"from 0 to n-1" is i < n. Therefore, the loop will run until i=n-1, and that will be its last run. Same for
"from 0 to n-2" is i < (n-1).

vaha · #8 15-May-2005, 17:55

problem is solved

CPP / C++ / C Code:

int k=0;

  for (int i=0; i<n; i++){
         if (a[i] != z)
                   a[k++] = a[i];
                     }
                       n = k;
   for(k=0;k<n;k++) printf("%d",a[k]);

thaks all for help.

WaltP · #9 15-May-2005, 23:58

Quote:

Originally Posted by vaha

problem is solved

Much better. But I had to reformat your code so it could be read:

CPP / C++ / C Code:

int k=0;

for (int i=0; i<n; i++)
{
    if (a[i] != z)  a[k++] = a[i];
}
n = k;
for(k=0;k<n;k++) printf("%d",a[k]);

Read that tutorial.... It'll help.

vaha · #10 18-May-2005, 12:23

Quote:

by WaltP

Stand over the user with a baseball bat ready to swing.....

Not easily. This takes a completely different form of input than you probably can do at the moment. After a few more weeks of class this will be easier.

nice.
To prevent entering letters and sings.
I have something like this:

CPP / C++ / C Code:

do {
      printf(" Enter only numbers ");
      scanf(" %d ", &element);
     }
while(element >= "ASCii code (0)" && element <= "ASCii code (9)");

if this work do i need to #include some library?

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