sorting an array such that absolute values are sorted and positive values are printed before negative values

Question

for the given code

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>

void swap(int *xp, int *yp)
{
    int temp = *xp;
    *xp = *yp;
    *yp = temp;
}

void selectionSort(int arr[], int n)
{
int i, j, min_idx;

for (i = 0; i < n-1; i++)
{
    min_idx = i;
    for (j = i+1; j < n; j++)
      if (abs(arr[j]) < abs(arr[min_idx]))
        min_idx = j;
    if (abs(arr[j]) == abs(arr[min_idx])){
        if (arr[j] < arr[min_idx])
      min_idx = j;
    }
    swap(&arr[min_idx], &arr[i]);
}
}
int main()
{
int N;
scanf("%d", &N);
int i,t;
int T[N];
for(i=0;i<N;i++){
    scanf("%d",&T[i]);
}
selectionSort(T, N);
for(i=0;i<N;i++)
{printf("%d\n",T[i]);}
if(T==NULL)
{
printf("0\n");
}
 return 0;}

positive values are printed before negative values what should I do to get an output {1,2,-2,3-5,6,-7,11,-21,33} for input 10 {-21,2,11,3,-7,-2,33,-2,6,1} code URL https://ide.geeksforgeeks.org/dbGpvPBuV1

Is there a typo in the input you show? It does not contain a `-5`, but there is a `-5` in the desired output you show. — Eric Postpischil, Jun 06 '21 at 10:55
When discussing the input and output of a program, show it **exactly** as it is in the computer. Do not add extra braces or commas. Presumably your actual input is something like `10 -21 2 11 3 -7 -2 33 -5 6 1`, not `10 {-21,2,11,3,-7,-2,33,-2,6,1}`. Adding these extra characters can confuse readers. — Eric Postpischil, Jun 06 '21 at 10:56

score 0 · Answer 1 · answered Jun 06 '21 at 11:10

Your loop on j fails to use braces to enclose all the statements you want in the loop. Your code is:

    for (j = i+1; j < n; j++)
        if (abs(arr[j]) < abs(arr[min_idx]))
            min_idx = j;
    if (abs(arr[j]) == abs(arr[min_idx])){
        if (arr[j] < arr[min_idx])
            min_idx = j;
    }
}

but it should be:

    for (j = i+1; j < n; j++) {
        if (abs(arr[j]) < abs(arr[min_idx]))
            min_idx = j;
        if (abs(arr[j]) == abs(arr[min_idx])){
            if (arr[j] < arr[min_idx])
                min_idx = j;
        }
    }

Also, since you want positive numbers first, arr[j] < arr[min_idx] should be arr[j] > arr[min_idx].

Generally, do not declare loop indices outside a loop. Delete the line int i, j, min_idx;. Change for (i = 0; i < n-1; i++) to for (int i = 0; i < n-1; i++), change for (j = i+1; j < n; j++) to for (int j = i+1; j < n; j++), and change min_idx = i; to int min_idx = i;. If you had written the code this way in the first place, the compiler would have warned you about the lines erroneously outside the loop because the declaration of j would not be in scope for those lines. You would have found the error sooner.

sorting an array such that absolute values are sorted and positive values are printed before negative values

1 Answers1