So say I have two arrays intdataArray[10] = {61 34 46 114 73 29 13 93} and int *pointerDataArray[10] which has the pointers of the dataArray in the same respective index. How would I be able to sort the array through pointers and get the sorted array but also while still being able to print the original array.
My bubble sort is working but it is also changing dataArray as well.
This is the wanted output(correct)
dataArray before sort: 61 34 46 114 73 29 13 93
pointerArray before sort: 61 34 46 114 73 29 13 93
dataArray after sort: 61 34 46 114 73 29 13 93
pointerArray after sort: 13 29 34 46 61 73 93 114
This is the output I am getting(wrong)
dataArray before sort: 61 34 46 114 73 29 13 93
pointerArray before sort: 61 34 46 114 73 29 13 93
dataArray after sort: 13 29 34 46 61 73 93 114
pointerArray after sort: 13 29 34 46 61 73 93 114
Here is my code
#include <iostream>
#include <fstream>
using namespace std;
int readFile(string filename, int dataArray[10], int *pointerDataArray[10]);
void pointerSort(int dataArray[],int *pointerDataArray[] , int length);
void swapIntPtr(int *p1, int *p2);
void displayDataArray(int dataArray[], int length);
void displayPointerArray(int *pointerDataArray[], int length);
int main() {
int dataArray[10] = {};
int *pointerDataArray[10];
int length = readFile("arrayData.txt", dataArray, pointerDataArray);
cout << "dataArray before sort: ";
displayDataArray(dataArray, length);
cout << "pointerArray before sort: ";
displayPointerArray(pointerDataArray, length);
cout << endl;
pointerSort(dataArray, pointerDataArray, length);
cout << "dataArray after sort: ";
displayDataArray(dataArray, length);
cout << "pointerArray after sort: ";
displayPointerArray(pointerDataArray, length);
}
int readFile(string filename, int dataArray[10], int *pointerDataArray[10]) {
ifstream inputFile(filename);
if (inputFile.is_open()) {
int length;
inputFile >> length;
for (int i = 0; i < length; i ) {
inputFile >> dataArray[i];
pointerDataArray[i] = &dataArray[i];
}
return length;
}
return -1;
}
void pointerSort(int dataArray[],int *pointerDataArray[] , int length){
int i, j;
for (i = 0; i < length-1; i )
for (j = 0; j < length-i-1; j )
if (dataArray[j] > dataArray[j 1]) {
swapIntPtr(&dataArray[j], &dataArray[j 1]);
}
}
void swapIntPtr(int *pointer1, int *pointer2) {
int pSwap = *pointer1;
*pointer1 = *pointer2;
*pointer2 = pSwap;
}
void displayDataArray(int dataArray[], int length){
for (int i = 0; i < length; i ) {
cout << dataArray[i] << " ";
}
cout << endl;
}
void displayPointerArray(int *pointerDataArray[], int length){
for (int i = 0; i < length; i ) {
cout << *pointerDataArray[i] << " ";
}
}
CodePudding user response：
In your pointerSort function, you're calling the swapIntPtr function in the addresses of both integers. It actually changes the content behind the pointers, i.e., it swaps the integers. Instead, you want to call swapIntPtr with the address of the pointers and the function needs to change the pointers.
void swapIntPtr(int **pointer1, int **pointer2) {
int* pSwap = *pointer1;
*pointer1 = *pointer2;
*pointer2 = pSwap;
}
Aso, make sure to change the declaration on top.
Then, you need to change your sort function to run on the pointerDataArray
void pointerSort(int dataArray[],int *pointerDataArray[] , int length){
int i, j;
for (i = 0; i < length-1; i )
for (j = 0; j < length-i-1; j )
if (*pointerDataArray[j] > *pointerDataArray[j 1]) {
swapIntPtr(&pointerDataArray[j], &pointerDataArray[j 1]);
}
}
The complete code would look like this:
#include <iostream>
#include <fstream>
using namespace std;
int readFile(string filename, int dataArray[10], int *pointerDataArray[10]);
void pointerSort(int dataArray[],int *pointerDataArray[] , int length);
void swapIntPtr(int **p1, int **p2);
void displayDataArray(int dataArray[], int length);
void displayPointerArray(int *pointerDataArray[], int length);
int main() {
int dataArray[10] = {};
int *pointerDataArray[10];
int length = readFile("arrayData.txt", dataArray, pointerDataArray);
cout << "dataArray before sort: ";
displayDataArray(dataArray, length);
cout << "pointerArray before sort: ";
displayPointerArray(pointerDataArray, length);
cout << endl;
pointerSort(dataArray, pointerDataArray, length);
cout << "dataArray after sort: ";
displayDataArray(dataArray, length);
cout << "pointerArray after sort: ";
displayPointerArray(pointerDataArray, length);
}
int readFile(string filename, int dataArray[10], int *pointerDataArray[10]) {
ifstream inputFile(filename);
if (inputFile.is_open()) {
int length;
inputFile >> length;
for (int i = 0; i < length; i ) {
inputFile >> dataArray[i];
pointerDataArray[i] = &dataArray[i];
}
return length;
}
return -1;
}
void pointerSort(int dataArray[],int *pointerDataArray[] , int length){
int i, j;
for (i = 0; i < length-1; i )
for (j = 0; j < length-i-1; j )
if (*pointerDataArray[j] > *pointerDataArray[j 1]) {
swapIntPtr(&pointerDataArray[j], &pointerDataArray[j 1]);
}
}
void swapIntPtr(int **pointer1, int **pointer2) {
int* pSwap = *pointer1;
*pointer1 = *pointer2;
*pointer2 = pSwap;
}
void displayDataArray(int dataArray[], int length){
for (int i = 0; i < length; i ) {
cout << dataArray[i] << " ";
}
cout << endl;
}
void displayPointerArray(int *pointerDataArray[], int length){
for (int i = 0; i < length; i ) {
cout << *pointerDataArray[i] << " ";
}
}
CodePudding user response：
You pass the pointerDataArray to the pointerSort function but you don't even use it. What you actually need to do is to be able to sort the array of pointers without even passing the dataArray into the function:
void pointerSort(int *pointerDataArray[], int length){
int i, j;
for (i = 0; i < length-1; i )
for (j = 0; j < length-i-1; j )
if (*pointerDataArray[j] > *pointerDataArray[j 1]) {
swapIntPtr(pointerDataArray[j], pointerDataArray[j 1]);
}
}
Swapping the pointers shall be changed too. I would recommend to use std::swap anyway, but just for the reference here is a modified version of your function:
void swapIntPtr(int* &pointer1, int* &pointer2) {
int *tmp = pointer1;
pointer1 = pointer2;
pointer2 = tmp;
}