How to compare an address to another address and replaces the value stored in that address?

Code:
//This program prints the initialize value and the addresses of  the
//elements inside the array. This proram also allows the user to change
//the address of the hardcoded number in the program.

#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>

#define ARRAY_SIZE 4

int main(){
    //Declare variable
    int x=1,rep;
    char error[128];
    // Declare array
    int arr[]={1,2,3,4};
    //Declare pointer
    int *ptr;
    
    system("cls");
    //Show value of array elements
    printf("The value of elements inside the array:\n\n");
    for(int i=0;i<ARRAY_SIZE;i++){
            printf("Value of element %d: %d\n",i,arr[i]);
    }
    //Print addresses of array elements
    printf("The addresses of elements inside the array:\n\n");
    for(int i=0;i<ARRAY_SIZE;i++){
    ptr = &arr[i];
        printf("Address of element %d: %p\n",i,ptr);
    }
    
    //Show value of variable
    printf("Value of x: %d\n",x);
    //Print address of variable
    ptr=&x;
    printf("Address of x: %p\n",ptr);
This is the part that i really don't know. The user should in put any of the address printed by the program, after inputting the address the program asks the user to change the value stored in that address..

//Input address
int temp=0;
printf("Please input an address: ");
scanf("%d",&temp);

*ptr = temp;

//Print input
printf("Your input: %p\n", *ptr);

Code:
    printf("Please press the spacebar to continue!!");
    getche();
    system("cls");
    do{
       system("cls");
       printf("Do you want to repeat the computation?\n\n");
       printf("1 - Yes\n");
       printf("2 - No\n");
       scanf("%s",&error);
       rep=atoi(error);
       switch(rep){
                   case 1:
                        main();
                        break;
                   case 2:
                        break;
                   default:
                           system("cls");
                           printf("Invalid input. Please try again!!!\n");
                           printf("Please press the spacebar to continue!!");
                           getche();
                           break;   
                   }
       }while(rep>2||rep<1);
    }