CODEWITHSUNDEEP
c++algorithminsertion-sort
Luke
Luke

Reputation: 155

Why is my insertion sort algorithm altering numbers in the given array? (C++)

I have a C++n insertion sort function template, and it works fine when I give the function an array of integers, but when I give the function an array of doubles, although the array is indeed sorted afterwards, for some reason it alters the numbers in the sorted array.

The code:

#include <iostream>
#include <stdlib.h>

using namespace std;

template <typename T>
void insertionSort(T ary[10], int size)
{   
    // Printing unsorted array
    cout << "Array before sorting: [";
    for (int i = 0; i < size; i++)
    {
        cout << ary[i] << ", ";
    }
    cout << "]" << endl;

    // Beginning of sorting
    int j, t;
    for(int i = 1; i < size; i++)
    {
        for (int i = 0; i < size; i++)
        {
            j = i;

            while(j > 0 && ary[j] < ary[j-1])
            {
                t = ary[j];
                ary[j] = ary[j-1];
                ary[j-1] = t;
                j--;
            }
        }
    }

    // Printing sorted array
    cout << "Array after sorting: [" ;
    for (int i = 0; i < size; i++)
    {
        cout << ary[i] << ", ";
    }
    cout << "]\n" << endl;
}

int main()
{
    cout << "*** INTEGER ARRAY INSERTION SORT ***" << endl;
    int intAry[10] = {0};
    for (int i = 0; i<= 9; i++)
    {
        intAry[i] = rand() % 100;        
    }

    insertionSort(intAry, 10);

    cout << "*** DOUBLE ARRAY INSERTION SORT ***" << endl;
    double dAry[10] = {0};
    for(int i = 0; i<=9; i++)
    {
        dAry[i] = (double)rand() / RAND_MAX * 100;
    }

    insertionSort(dAry, 10);

    return 0;
}

The output:

enter image description here

You can see here that it changes the number in the array of doubles, like 14.1603 to 14.

Thank you for any help!

Upvotes: 0

Views: 80

Answers (1)

Hasan Can
Hasan Can

Reputation: 38

The problem is, you want to compare the double numbers, but when you're going through the loop, you use the int i and int j variables. Result is incorrect due to incompatible data type. if you covert "double" the "int" data types, your problem will be solved.

Also you must change your array type to double.

Upvotes: 1

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