How to reverse the array for Cpp

Question

I am trying to command my program to reverse a set of random array numbers. I get my program to come up with 10 digits, (ranging from 60-100) and when the random array is generated, I get it to give me 4 options; ex:

66 75 84 93 82 61 66 99 85 93

R - for reverse. (this will reverse the array set to[93 85 99 66...84 75 66])

S - for search. (this will prompt you to search a number and read what line it'll be located in. )

E - for exit. (to exit the program )

A - for add.. (this will add up all the random array number set.)

Everything works great but the only issue I am having is that it won't reverse the random generated array set. I thought I promoted the correct command. I need help with this, please keep in mind I am new to C++.

#include <iostream>
#include <stdlib.h>
#include <time.h>

 using namespace std;

 int main ()
 {
  srand(time(0));
  int arr[10],i,sum;
  bool found;
  char choice;
  for (i = 0; i < 10; i++){
    arr[i] = rand() % 30 + 60;
   }


cout << "The random generated array is: \n";
for (i = 0; i <10; i++){
    cout << arr[i] << "  ";
}

cout << "\n\nR[reverse]\t[S]search\t[E]exit\t\t[A]add\nSelect an option: ";
cin >> choice;
switch (choice){
main ();
    case 'R':
    case 'r':
        cout << "\nThe reversed array is: ";
            for (i = 9; i >=0; i--)
            cout << endl << endl << "------------------------------" << endl;

   main ();
       case 'A':
       case 'a':
        cout << "\nThe sum of the array element is ";
        sum = 0;
            for (i = 0; i < 10; i++) sum += arr[i];
            cout << sum << "\n";
            cout << endl << endl << "----------------------"    << endl;
   main ();
        case 'S':
        case 's':
        cout << "\nPlease insert an element to find: ";
        int find;
        found=false;
        cin >> find;
            for (i = 0; i<10; i++){
                if(arr[i] == find){
                    if(i ==0)
            cout << "\nThe number " << find << " has been found at the 1st position" << endl; 
                else if(i == 1) cout << "\nThe number " << find << " has been found at the 2nd position" << endl;
                else if(i == 2) cout << "\nThe number "  << find << " has been found at the 3rd positon" << endl;
                else if(i == 3) cout << "\nThe number " << find << " has been found at the 4th position" << endl;
                else if(i == 4) cout << "\nThe number " << find << " has been found at the 5th position" << endl;
                else if(i == 5) cout << "\nThe number " << find << " has been found at the 6th position" << endl;
                else if(i == 6) cout << "\nThe number " << find << " has been found at the 7th position" << endl;
                else if(i == 7) cout << "\nThe number "  << find << " has been found at the 8th position" << endl;
                else if(i == 8) cout << "\nThe number " << find << " has been found at the 9th position" << endl;
                else if(i == 9) cout << "\nThe number " << find << " has been found at the 10th position" << endl;
                found = true;
                }
            }
            if(found) cout << "\nElement not found\n";
            cout << endl << endl << "----------------------" << endl;
        main();

        case 'E':
        case 'e':
            break;
}
return 0;
   }

Edited: Ok I just posted the entire code so you can see a little bit better in debt. That was my fualt. sorry.

Where are you trying to reverse the array? Looks like you run a loop that prints out what is supposed to happen after the reverse. Also, if you are new to C++, great time to learn to use std::array<int, 10> or std::vector<int> and en.cppreference.com/w/cpp/algorithm/reverse — RyanP
– RyanP, Commented Jan 13, 2017 at 16:41
did you mean to cout << arr[i] where you are printing the reversed array? — Kenny Ostrom
– Kenny Ostrom, Commented Jan 13, 2017 at 16:42
Do you want to actually reverse the array, or just print it out in reverse order? — Caleb
– Caleb, Commented Jan 13, 2017 at 16:57

score 2 · Accepted Answer · 2017-01-13 17:03:53Z

2

Use the std::reverse() function to reverse the order:

#include <iostream>
#include <algorithm>

int main(){

    int myArray[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    std::reverse(std::begin(myArray), std::end(myArray));
    for (const auto& arr : myArray) {
        std::cout << arr << std::endl;
    }
    return 0;
}

Or make a simple function:

#include <iostream>

void reverseArray(int a[], int n)
{
    int temp;
    for (int i = 0; i < n / 2; i++)
    {
        temp = a[n - i - 1];
        a[n - i - 1] = a[i];
        a[i] = temp;
    }
}

int main(){

    int myArray[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    reverseArray(myArray, 10);
    for (const auto& arr : myArray) {
        std::cout << arr << std::endl;
    }
    return 0;
}

You should consider using std::vector or some other sequential container instead.

edited Jan 13, 2017 at 17:03

answered Jan 13, 2017 at 16:50

user1593881

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2 Comments

Caleb Over a year ago

This seems like a case where the OP is probably learning how to reverse an array, perhaps as part of a class assignment. If that's the case, using a library function is easy but not educational.

user1593881 Over a year ago

@Caleb I think so too. I have also included a simple user defined function.

HRgiger · Accepted Answer · 2017-01-13 16:45:31Z

0

You dont print ith element of array which is arr[i], you just print dashes.

cout << endl << endl << "------------------------------" << endl;

Also you handle lower and upper case differently:

case 'R':
case 'r':

which 'r' is not mentioned in your help option.

answered Jan 13, 2017 at 16:45

HRgiger

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2 Comments

Kenny Ostrom Over a year ago

that's how you handle two cases the same

HRgiger Over a year ago

@KennyOstrom well there are some cases linuxcommand.org/man_pages/ls1.html

NikolaTECH · Accepted Answer · 2017-01-13 16:55:16Z

0

To reverse array, you have to #include <algorithm>. The syntax looks like this: reverse(arrayName, arrayName + arraySize);

In your case, it should be written like this: reverse(arr, arr + 10);

answered Jan 13, 2017 at 16:55

NikolaTECH

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