CODEWITHSUNDEEP
c++arraysoverwrite
jshapy8
jshapy8

Reputation: 2051

In C++: How to overwrite an element to an array by moving entries below it up by one

I am trying to "delete" an element in my array. I have been told by those who know C++ better than I do that to accomplish this I must move all entries below the one I want to delete up by 1. Afterwards, I must decrease by 1 the variable keeping track of the size of the array. So I wrote this code to accomplish that:

cout << "Type the number of the inventory entry you would like to delete:\n";
        cin >> entryToDelete;

        for ( count = 0 ; count < (entryToDelete - 1) ; count++)
                list[count] = list[count + 1];

position--;

I previously displayed for the user the entries in the array as #1, #2, #3, etc while their subscripts are 0, 1, 2, etc... That is why I put entryToDelete - 1. position is the variable that keeps track of the size of the array. Anyway, I use this code to output the array so I can check if the code worked:

for (int count = 0 ; count <= position ; count++)
        {
                cout << "Entry #" << (count + 1) << endl;
                cout << "ISBN: " << list[count].ISBN << endl
                     << "Author: " << list[count].Author << endl
                     << "Title: " << list[count].Title << endl
                     << "Quantity: " << list[count].Quantity << endl
                     << "Price: " << list[count].Price << endl << endl;
        }

For some reason, no matter what number I input to delete, the last element in the array is deleted. I have tried several modifications, such as changing the order of the array elements to modify: i.e. list[count + 1] = list[count], but this does not give me what I want.

Unfortunately, I am restricted from using vectors.

Upvotes: 0

Views: 1455

Answers (3)

Mo Beigi
Mo Beigi

Reputation: 1765

This should do it. It moves all the elements into place and removes the entry you wanted to delete.

  for ( size_t count = entryToDelete; count < arraySize - 1 ; ++count)
    list[count] = list[count + 1];

  --arraySize;

Upvotes: 1

sam
sam

Reputation: 2033

You need to move all elements to the right of that element one to the left.

enter image description here

Here is a simple code that shows how to move elements to the left

#include <iostream>
using namespace std;

int main() {
    int arr[10]=  {0,1,2,3,4,5,6,7,8,9};
    int numToDelete = 5;

    for (int i = numToDelete; i < sizeof(arr)/sizeof(arr[0]); i++ )
    {
        arr[i] = arr[i+1];
    }

    arr[sizeof(arr)/sizeof(arr[0]) - 1] = 0;

    for(int i = 0; i < sizeof(arr)/sizeof(arr[0]); i++)
    {
        cout << arr[i] << endl;
    } 

    return 0;
}

Upvotes: 2

Oswald
Oswald

Reputation: 31647

Move the entries following the deleted element to the front by one.

Upvotes: 1

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