Array Sorting Issues in C++

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I am trying to make a program that sorts an array without using the sort function (that won't work with objects or structs). I have made the greater than one work, but the less than one keeps changing the greatest element in the array to a one and sorting it wrong, and when used with the greater than function, the first element is turned into a large number. Can someone please help me fix this or is it my compiler.

void min_sort(int array[], const unsigned int size){
    for(int k = 0; k < size; k++) {
        for(int i = 0; i < size; i++) {
            if(array[i] > array[i+1]){
                int temp = array[i];
                array[i] = array[i+1];
                array[i+1] = temp;
            }
         }
     }
}
sorting arrays c++
4 Answers

You are not looping correctly. Looks like you are trying bubble sort which is:

void min_sort(int array[], const unsigned int size){
    for(int k = 0; k < size; k++)
        for(int i = k+1; i < size; i++)
            if(array[i] < array[k]){
                int temp = array[i];
                array[i] = array[k];
                array[k] = temp;
            }
}
user_8874200 
void min_sort(int array[], const unsigned int size)
{
  for(int i=0;i<size-1;i++)
  {
    for(int j=0;j<size-1-i;j++)
    {
      if(array[j]>array[j+1])
      {
        swap(array[j] , array[j+1]);
      }
    }
  }
}

I see that you are trying to implement the bubble sort algorithm. I have posted the code for bubble sort here. In bubble sort you basically compare the element at an index j and the element next to it at index j+1. If array[j] is greater than array[j+1] , you swap them using the swap() function or by using the temp method. The outer loop will run size - 1 times , and the inner loop will run size - 1 - i times because the last element will already be in place.

For Example we have an array of size 4 with elements such as :

array[i] = [100,90,8,10]

The bubble sort will sort it in the following steps :

90,100,8,10 90,8,100,10 90,8,10,100

8,90,10,100 8,10,90,100

8,10,90,100

See, the use of size-1-i . You can see the nested loop runs less number of times in each iteration of the outer loop.

user_120277250

There is only one mistake that your 2nd loop condition should be: i < size -1.

So it should be:

for (int i = 0; i < size -1; i++)
user_170593760

Your attempt at bubble sort is basically correct, you just have an out of bounds issue with your inner loop. During the inner loop's last run, i == size - 1, therefore i + 1 is equal to size, thus data[i+1] is out of range. Simply change the condition of your for to be i < size - 1.

Working example: https://godbolt.org/z/e5ohWPfTz

user_106860480
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