Thread: Insert element after the last element in array in c

Hello everyone

I have an array say int array[30]. I want to add elements to this array. New elements needs adding after the last element. Is there any simple way to do this?
The structure of the code is somewhat as under

Code:

int main()
{
int array[30],x;
scanf("%d",&x);

//i need to traverse through the array till it reaches the last element (if there are any elements present and then add the new element after the last element
//also it would be good to check that the size does not exceed 30
return 0;
}

any suggestion would be appreciated.thanks

Hello Laserlight
How r u?thanks for your reply

Ok, so far I have managed to write the program as follows.

The code creates an array, checks if the element to be added is already present in the array list.If not present added to the array otherwise prints out "id present".However, when I call the display function it displays the array 30 times.But i want to display only the elements that is present in the array. Thats it.How do i proceed from here.Also please suggest is the code is alright?

Please help.Thank u

Code:

#include <stdio.h>
#define MAX 30

int find_dev(int a[],int data)
{
   int i;
   for (i=0; i<MAX; i++)
   {
     if (a[i] == data)
     {
        return(data);
     }
   }
   return(-1); 
}
 
int add_id(int a[],int data)
{
int i;
for(i=0;i<30;i++)
 a[i] = data;
printf("ID added %d\n",a[i-1]);
}

int display(int a[])
{
int i;
for(i=0;a[i]!=0;i++)  
printf("ID added %d\n",a[i]);
}

int main()
{
int array[30]={};
int i,ret;
int data;

  while(1)
  {
    scanf("%d",&data);
    ret=find_dev(array,data);
    if(ret==-1)
      {
    add_id(array,data);
    display(array);
      }
      else
      {
    printf("ID already exists");
      }
  } 
return 0;
}

The code creates an array, checks if the element to be added is already present in the array list.If not present added to the array otherwise prints out "id present".However, when I call the display function it displays the array 30 times.But i want to display only the elements that is present in the array. Thats it.How do i proceed from here.Also please suggest is the code is alright?

Look at your "add_id()" function. You're not adding the data to the end of the array - you're overwriting the entire array with that value.

laserlight suggested keeping track of the number of elements in use. If you go this route, then you should use a variable in "main()" to track this information and pass it to your other functions as needed (so you know what index the next value goes, and how much of the array to print).

It appears that now, you're using a sentinel value of 0 to determine the end of valid data in the array. This approach works too, as long as zero is not considered valid data.

Suggested improvements:

• Be more consistent with your indentation.
• The functions "add_id()" and "display()" are supposed to return an int, but are not returning anything. Either return a value, or make their return types void.
• When passing an array to a function, it's good practice to also pass the size of the array
• You define a constant that is used to iterate through the array in "find_dev()", but you're still using the magic number 30 in "add_id()" and "main()".