Add an element to an array at a particular location

[Raman009]

Here is my attempt:

int add(int e , int size , int a[] , int loc){
    int flag = -1 ;
    if(loc < size){
        flag = 0 ;
        for(int i=size; i<=(loc-1);i--){
            a[i]=a[i-1]; // moving elements forwards to create space for element
        }
        a[loc-1]= e;
    }
    return flag ;
}

However in my attempt I lose the element at location .
for example:
If I want to add an element 4 at location 2 in the array :
Original Array : 1 3 4 5 9
Expected ans : 1 2 3 4 5 9
Answer that I get : 1 2 4 5 9 * "where * is equal to any number"
I lose the element 3 and this is not the correct answer .

I am entering the location starting from 1 and then I adjust the calculations in the function given above. This function is a part of another program. If you need that to find the error , please tell me . Thanks

[soranz]

What is 'size' defined as exactly ?
Nevertheless, a[] is presumably writing out of bounds. If you did this earlier:

a[] = {1, 3, 4, 5, 9};
Where is there room for the '2' ?
After a[] is initialized its size cannot be changed.

The way to do this is:
1- with vectors which can be resized dynamically or,
2- by passing in a second array b[newsize] which is the size that u want ur new array to be and copy each element 1 by 1 from a[] into b[] until ur loop hits the 'loc' element which u can then insert into b[] and then continue adding the rest of the elements from a[]
3- if u know beforehand how big a[] will be, u could (***) size it as such at initialization and add extra 'dummy' zeros to the end like this: a[] = {1, 3, 4, 5, 9, 0} Then u can use ur sorting algorithm with ur example which will remove that extra zero to make the desired output.

Also, ur for loop for(int i=size; i<=(loc-1);i--) never occurs. U want i>=(loc-1) instead

[AbstractionAnon]

What if loc is >= size?
What if loc is > than the size of the array?

[ne555]

While the condition is met, the loop is executed.
Also, if you defined your array to be of n elements then it cannot hold n+1 elements.

[Raman009]

Well , the silly mistake in for loop changed the situation.
Here's the complete code for the program however , it still shows some errors in the sort() function.

#include<iostream>
#include<cstdlib>
using namespace std ;

int search(int e,int size, int a[]){
    int loc = -1 ;
    for(int i=0 ; i<size; i++){
        if(a[i]== e){
            loc=i;
            break;
        }
    }
    return loc ;
}

int del(int e,int size, int a[]){
    int loc = search(e,size,a);
    if(loc != -1){
        for(int i=loc ; i<size ; i++){
            a[i]=a[i+1];
        }
        size = size - 1;
    }
    return loc ;
}

int add(int e , int size , int a[] , int loc){
    int flag = -1 ;
    if(loc < size){
        flag = 0 ;
        for(int i=size; i>=(loc-1);i--){
            a[i]=a[i-1];
        }
        a[loc-1]= e;
    }
    return flag ;
}

void sort(int size , int a[]){
    for(int pass=1; pass <= size-1; pass++){
      for(int j=0;j <= (size-pass)-1; j++){
        if(a[j] > a[j+1]){
             int temp ;
             temp = a[j];
             a[j] = a[j+1];
             a[j+1] = temp ;
            }
        }
    }
    cout<<"\nSorted Array";
    for(int k=0;k<size;k++){
        cout<<" "<<a[k];
    }
}

int main () {
    const int size = 10 ;
    int arr[size] = {134,32,45,23,-1,0,37,23,17,10};
    int loc = -1 ;
    int e , de ,ans ;
    cout<<"\t\t\t\tARRAY OPERATIONS";
    while(true){
    cout<<"\n\n1. Traversal.";
    cout<<"\n2. Search.";
    cout<<"\n3. Deletion";
    cout<<"\n4. Addition.";
    cout<<"\n5. Sort.";
    cout<<"\n6. Exit.";
    cout<<"\nWhich operation would you like to carry ";
    cin>>ans;
    switch(ans){
        case 1 :
        cout << "\nTraversal:\n";
        for(int i=0 ; i<10; i++){
            cout<<" "<<arr[i];
        }
        break;

        case 2 :
            cout << "\n\nEnter the element to search ";
            cin >> e;
            if((loc=search(e,size,arr))!= -1) {
                cout<<"\nThe location of the element is "<< (loc+1);
            }else {
                cout<<"\nElement not found !!";
            }
        break;

        case 3 :
            cout <<"\n\nEnter the element to delete";
            cin >> de ;
            if(del(de,size,arr)!= -1 ){
                cout << "\nElement deleted successfully !!";
                cout << "\nNew Array: ";
                for(int i=0 ; i<(size-1);i++){
                cout<<" "<<arr[i];
            }
            }else {
                cout << "Element not found !!";
            }
        break;

        case 4 :
            cout<<"\nEnter any element at a particular location(ele loc)";
            cin>>e>>loc;
            if(add(e,size,arr,loc)!= -1 ){
                cout<<"\nElement added successfully!!";
                cout<<"\nNew Array:";
                for(int i=0;i<(size+1);i++){
                    cout<<" "<<arr[i];
                }
            }else {
                cout<<"Element could not be added !!";
            }
        break;

        case 5 :
            sort(size,arr);
        break;

        case 6:
            exit(0);
            break;
        default:
        cout<<"Invalid argument. Exiting program...";
    }
   }
return 0 ;
}

The errors have been resolved. If any other suggestions are there , you are welcome ..thanks

[soranz]

in ur 'sort' function int temp ; should be declared outside of those loops...

what exactly is the issue with sort ?

[Raman009]

The issue has been resolved . Initially it used to copy the garbage value from the end of the array as well ie a[size]. So I just changed the loop from (size-pass) to (size-pass)-1. Now it doesn't compare the last value with the value at
a[size] ie a[size-1] > a[size]. That solved my problem.
btw thanks for replying ..

[soranz]

np :D
yes, sorting subsets of an array while staying in bounds of that array can be a pain in the **array** !!!