integar array palindrome checker - c++

Question

i made this program to make a function to check if integar array is palindrome or not.it is always giving output that it is not a palidrome on every input. can you plz help me out?
code:
#include<iostream>
using namespace std;
void palindrome(int[],int[],int);
int main()
{
int size=5;
int array1[size];
int array2[size];
palindrome(array1,array2,size);
}
void palindrome(int array1[],int array2[],int size)
{
size=5;
int l=0;
cout<<"enter your array=";
for(int i=0;i<size;i++)
{
cin>>array1[i];
}
for(int i=0;i<size;i++)
{
array2[i]=array1[size-i];
}
if(array1==array2)
{
cout<<"given array is palindrome.";
}
else{
cout<<"given array is not palindrome.";
}
}

Answer 1

You can't compare two arrays with ==, it will only compare if the array's address are equals, so different arrays never equals, we can switch it to std::equal
There is one memory issue with array2[i]=array1[size-i];, you will get a buffer overflow.
This is a slighly modified version of your code:
#include <iostream>
using namespace std;
void palindrome(int[], int[], int);
int main() {
int size = 5;
int array1[size];
int array2[size];
palindrome(array1, array2, size);
}
void palindrome(int array1[], int array2[], int size) {
size = 5;
int l = 0;
cout << "enter your array=";
for (int i = 0; i < size; i++) {
cin >> array1[i];
}
for (int i = 0; i < size; i++) {
array2[i] = array1[size - i - 1];
}
if (std::equal(array1, array1 + size, array2, array2 + size)) {
cout << "given array is palindrome.";
} else {
cout << "given array is not palindrome.";
}
}
It's recommended to use std::vector instead of the C style array:
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
void palindrome(int);
int main() {
int size = 5;
palindrome(size);
}
void palindrome(int size) {
std::vector<int> vec(size);
cout << "enter your array=";
for (int i = 0; i < size; i++) {
cin >> vec[i];
}
std::vector<int> rev_rec{vec.rbegin(), vec.rend()};
if (vec == rev_rec) {
cout << "given array is palindrome." << std::endl;
} else {
cout << "given array is not palindrome." << std::endl;
}
}
And we can also avoid the copy of vector, with reverse iterator:
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
void palindrome(int);
int main() {
int size = 5;
palindrome(size);
}
void palindrome(int size) {
std::vector<int> vec(size);
cout << "enter your array=";
for (int i = 0; i < size; i++) {
cin >> vec[i];
}
if (std::equal(vec.begin(), vec.end(), vec.rbegin(), vec.rend())) {
cout << "given array is palindrome." << std::endl;
} else {
cout << "given array is not palindrome." << std::endl;
}
}