输出中的特定递归逆向程序问题

Question

I completed my recursive reverse (array) C++ program however, it is outputting partially correctly, with an extra "10" which I believe is because my const int SIZE = 10. I am unsure about where I made the error(s) in my program and would like some advice on where the error has happened. Thank you. Any help will be greatly appreciated. This is the output I am receiving:

Original Array:   9   2   6  11   0  18   4  13   2   7
Reversed Array:   7   2  13   4  18   0327053270532705  10

The following is my code:

#include <iostream>
#include <cstdlib>
#include <iomanip>
#include <ctime>

const int SIZE = 10;
unsigned int seed = int (time(0));

using namespace std;

double random(unsigned int &seed);
void initialize(int a[]);
void print_array(int a[]);
void recursive_reverse_array(int a[], int[], int[]);

double random(unsigned int &seed)
{
  const int MODULUS = 15749;
  const int MULTIPLIER = 69069;
  const int INCREMENT = 1;
  seed  = ((MULTIPLIER *seed) + INCREMENT) % MODULUS;
  return double (seed)/double(MODULUS);
}

void initialize(int a[])
{
  for (int i = 0; i < SIZE; ++i)
     a[i] = (20 * (random(seed)));
}

void print_array (int a[])
{
  for (int i = 0; i < SIZE; ++i)
     cout << setw(4) << a[i];
  cout << endl;
}

void recursive_reverse_array(int a[],int num1, int num2)
{
  int k;
  if(num1 < num2)
  {
    a[num1] = a[num2];
    a[num2] = k;
    recursive_reverse_array(a, num1 + 1, num2 - 1);
  }
}

int main ()
{
  int arr[SIZE];
  cout << "Original Array:";
  initialize(arr);
  print_array(arr);
  recursive_reverse_array(arr, 0, SIZE - 1);
  cout << "Reversed Array:";
  print_array(arr);
  return 0;
}

Answer 1

Set int k = a[num1]; in your recursive_reverse_array function, and that should work. Currently, you have it uninitialized, which I believe gives you your partially correct output.

Answer 2

you are doing a silly mistake in your code. please see below code and replace your code with it.

   #include <iostream>
#include <cstdlib>
#include <iomanip>
#include <ctime>

const int SIZE = 10;
unsigned int seed = int (time(0));

using namespace std;

double random(unsigned int &seed);
void initialize(int a[]);
void print_array(int a[]);
void recursive_reverse_array(int a[], int[], int[]);

double random(unsigned int &seed)
{
  const int MODULUS = 15749;
  const int MULTIPLIER = 69069;
  const int INCREMENT = 1;
  seed  = ((MULTIPLIER *seed) + INCREMENT) % MODULUS;
  return double (seed)/double(MODULUS);
}

void initialize(int a[])
{
  for (int i = 0; i < SIZE; ++i)
     a[i] = (20 * (random(seed)));
}

void print_array (int a[])
{
  for (int i = 0; i < SIZE; ++i)
     cout << setw(4) << a[i];
  cout << endl;
}

void recursive_reverse_array(int a[],int num1, int num2)
{
  int k;
  if(num1 < num2)
  {
    k=a[num1];
    a[num1] = a[num2];
    a[num2] = k;

    recursive_reverse_array(a, num1 + 1, num2 - 1);
  }
}

int main ()
{
  int arr[SIZE];
  cout << "Original Array:";
  initialize(arr);
  print_array(arr);
  recursive_reverse_array(arr, 0, SIZE - 1);
  cout << "Reversed Array:";
  print_array(arr);
  return 0;
}

you have to use k = a[num1]; in your code. hope it will work.