Is there anyting wrong with this?

Androto · 10-11-2004, 09:49 AM

Code:

#include <iostream>
#include <cstdlib>

using namespace std;
int oddy (int x(1), int y);
int main()
  oddy;
  cout<< "\n";
          
  system("PAUSE");  
  return 0;
}

int oddy (int x, int y)
{
  while (x<=10)
  {
    y = x % 2;
    if (y==1)
    {
      cout << x << " is odd" << endl;
      x++;
    }
      else
    {
        cout << x << " is even" << endl;
      x++;
    }
  }
  return 0
}

Valmont · 10-11-2004, 01:28 PM

A lot

.
But first thing first. Try to use the CODE tags. Insert your code between [ code ] and [ /code ].
Here, compare these:

Code:

#include <iostream>
#include <cstdlib>

using namespace std;

void odd();
void odd(int x);

int main()
{
   odd();
   cout<<endl;
   
   odd(4);
   cout<<endl;
   
   system("PAUSE");
   return 0;
}

void odd()
{
   int x(0);
   while (x<=10)
   {
      if (x % 2 == 0)
         cout << x << " is even";
      else
         cout << x << " is odd";
      { ++x; cout<<endl; }
   } 
}

void odd(int x)
{
   if (x % 2 == 0)
      cout << x << " is even";
   else
      cout << x << " is odd";
}

The usage of these two functions are different, although they are fundamentally the same functions. If I could remove the double code, it will show. The core of the application is if (x % 2 == 0). So if could extract this test from both the functions, I could make things a little less memory consuming without critical speed (if any speed is lost to start with). And besides, we'd like to seperate messages from the critical functions. So I'll do that too. Later, when you build controllers and engines and alike (these do the "clever" part of a program), you'd like to seperate the views from everything else.

Code:

#include <iostream>
#include <cstdlib>

using namespace std;

bool odd(int x);
void odd_even_msg(bool m);
void range_test_odd();

int main()
{
   range_test_odd();
   system("PAUSE");
   return 0;
}

//////////////////////////////////////

bool odd(int x)
{
   if (x % 2 == 0)
      return false;
   else
      return true;
}

//////////////////////////////////////

void odd_even_msg(bool m)
{
   if(m)
      cout<<"is even"<<endl;
   else
      cout<<"is odd"<<endl;
}

/////////////////////////////////////////

void range_test_odd()
{
   for(int i = 0; i<11; ++i)
   {
      cout<<i<<' ';
      odd_even_msg( odd(i) );
   }
}

joe_bruin · 10-11-2004, 01:32 PM

yes, many things.

Code:

#include <iostream>
#include <cstdlib>

using namespace std;
//LONE BELOW: cannot declare a default value on a parameter when the following parameters do
// not have defaults.  this header does not match the function declaration
int oddy (int x(1), int y); 

int main() // opening brace?
  oddy; // this statement does nothing
  cout<< "\n"; // endl is generally preferred

  system("PAUSE");  // this doesn't work on my system.
  return 0;
}

// why is 'y' a parameter to oddy if its passed in value is not being used?
int oddy (int x, int y)
{
  while (x<=10)
  {
    y = x % 2;
    if (y==1)
    {
      cout << x << " is odd" << endl;
      x++;
    }
      else
    {
        cout << x << " is even" << endl;
      // x is incremented in two places.  why not have
      x++;  //a single increment outside the if/else statements?
    }
  }
  // why does this function return a value?  it does not compute
  //anything and does not detect any possible failures
  return 0 // semicolon
}

of course, compiling this would have told you most of these. is this what they give as college level homework assignments nowadays?