Using Multidimensional Arrays to Keep Track of Indices in C++ - c++

Question

I'm working on a project where I need to sort an array from least to greatest, but save the values of the indices. For example, with the array {2, 7, 8, 1, 3}, the sorted indices would be {3, 0, 4, 1, 2}. I thought that I could use a two dimensional array to accomplish this; I would add the index to each component, sort the array, then retrieve the original index from the second element. It hasn't been working for me as well as I hoped though, I have my current code below and it keeps giving me a segmentation fault. I don't know what I'm doing wrong, but I'm assuming its something in my for loops.
#include <iostream>
#include <algorithm>
using namespace std;
const int SIZE = 7;
int main()
{
int intArray[SIZE] = {5, 3, 32, -1, 1, 104, 53};
int i, j, k, l = 0;
int temp[SIZE][2];
//fills multidimensional array temp with data from intArray or index #
for(i = 0; i < 7; i++){
for(j = 0; j < 2; j++){
switch (j)
{
case '0':
temp[i][j] = *intArray;
break;
case '1':
temp[i][j] = i;
break;
}
}
}
sort(intArray, intArray + SIZE);
//prints each component of temp individually
cout << "Sorted Array looks like this." << endl;
for (k = 0; i < 7; i++){
for (l = 0; j < 2; i++){
cout << &temp[k][l] << endl;
}
}
return 0;
}

Answer 1

The following loop is much simpler and does what it should:
for(i = 0; i < 7; i++){
temp[i][0] = intArray[i];
temp[i][1] = i;
}
One error in your code is the line
temp[i][j] = *intArray;
This always assigns the 1st element of intArray.
The thing that causes the segmentation fault is probably the & in the output statement, just remove it.
Aside from that, I agree with the recommendation in the comment by RyanP.

Answer 2

Use std::map. The code will be the easiest. Test on cpp.sh
#include <iostream>
#include <map>
int main()
{
std::map<int,int>arr = {{5,0}, {3,1}, {32,2}, {-1,3}, {1,4}, {104,5}, {53,6}};
for(auto&x:arr) std::cout << x.first << " - > " << x.second << std::endl;
return 0;
}

Answer 3

I ended up using what Frank Puffer said and chose to use a simple bubble sort instead of using any of the built in functions. Here is a link to what my final program looked like http://ideone.com/cpEgGA
#include <iostream>
#include <algorithm>
using namespace std;
const int SIZE = 7;
int main()
{
int intArray[SIZE] = {5, 3, 32, -1, 1, 104, 53};
int i, j, k, l, m = 0;
int temp2[SIZE][2];
int indices[SIZE] = {};
for(i = 0; i < 7; i++){
temp2[i][0] = intArray[i];
temp2[i][1] = i;
}
cout << "Unsorted Array looks like this." << endl;
for (j = 0; j < 7; j++){
cout << temp2[j][0];
cout << " : ";
cout << temp2[j][1] << endl;
}
for(k = 0; k < SIZE; k++)
{
for(j = 0; j < SIZE-1-k; j++)
{
if(temp2[j+1][0] < temp2[j][0])
{
l = temp2[j][0];
temp2[j][0] = temp2[j+1][0];
temp2[j+1][0] = l;
l = temp2[j][1];
temp2[j][1] = temp2[j+1][1];
temp2[j+1][1] = l;
}
}
}
cout << "Sorted Array looks like this." << endl;
for (m = 0; m < SIZE; m++)
{
cout << temp2[m][0];
cout << " : ";
cout << temp2[m][1] << endl;
}
for(i = 0; i < SIZE; i++){
indices[i] = temp2[i][1];
}
cout << "Indices of Sorted Array look like this." << endl;
for(i = 0; i < SIZE; i++){
cout << indices[i] << endl;
}
return 0;
}