find the element you want

The outputs:

Input the length of array: 12
  1  3  3  8  7  2  2  7  2  5  4  1
scan and identify whether 1 exists or not
There is an element 1 in the array

The corresponding codes:

//step_1 generate a random array with random values
// step_2 suppose the value in array is prices of a specific prices
// step_3 write a function to get your most profit
#include <iostream>
#include <iomanip>
#include <ctime>
#include <cstdlib>
using namespace std;
void generate_array(int *&arr, int len);
void display_array(int arr[], int len);
int greedy_solution(int arr[], int len);
int dp_solution(int arr[], int len);
int find_existance(int arr[], int len, int ele);
int main()
{
    srand((unsigned)time(NULL));
    cout << "Input the length of array: ";
    int len;
    cin >> len;
    int *a;
    generate_array(a, len);
    display_array(a, len);
    int ele = rand() % 9;
    cout << "\nscan and identify whether " << ele << " exists or not" << endl;
    int identifier = find_existance(a, len, ele);
    if (identifier == 0){
        cout << "There is an element " << ele << " in the array" << endl; 
    }else{
        cout << "There isn't an element " << ele << " in the array" << endl;
    }
    free(a);
    return 0;
}
void generate_array(int *&arr, int len)
{
    arr = new int[len];
    for (int i = 0; i < len; i++){
        arr[i] = rand() % 8 + 1;
    }
}
void display_array(int arr[], int len)
{
    for (int i = 0; i < len; i++) {
        cout << setw(3) << arr[i] ;
    }
}
int find_existance(int arr[], int len, int ele)
{
    int flag = 1; // this means this program guess the element ele does not exist in the array 
    for (int i = 0; i < len; i++) {
        if (arr[i] == ele){
            flag = 0;
            break;
        }
    }
    return flag;
}
int greedy_solution(int arr[], int len)
{
    int max_profit = 0;
    for (int i = 1; i < len; i++) {
        if (arr[i] > arr[i-1]){
            max_profit += (arr[i] - arr[i-1]) ;
        }
    }
    return max_profit;
}
int dp_solution(int arr[], int len)
{
    int dp_0 = 0;
    int dp_1 = -arr[0];
    for (int i = 1; i < len; i++){
        dp_0 += max(dp_0, dp_1 + arr[i]);
        dp_1 += max(dp_1, dp_0 - arr[i]);
    }
    return dp_0;
}