Thread: beginner

please help a beginner to start writing the code:
I need to write a code that writes in a list numbers from 1 to 10 and then delets the even ones. i dont know what to start with. please help.

Originally Posted by jennilla

please help a beginner to start writing the code:
I need to write a code that writes in a list numbers from 1 to 10 and then delets the even ones. i dont know what to start with. please help.

Well I'm assuming you can start a new project and have the standard things included in your .cpp file: iostream, main function, namespaces... whatever....

A list of numbers from 1-10 is probably best put into an array. Since you want an array of integergs your decleration for this array would be something like

Code:

int myarray[10];

You said you're a beginner so I'm not quite sure if you understand that. the "int" part is the data type (you want to hold integers not floats or characters or anything else)... "myaray" is the name of your variable and the "[10]" indicates the capacity of your array.

If you want to declare and initiate your array all in one step you can do this

Code:

int myarray[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

there are other ways to initialize your array but that's the simplest.

to delete the even numbers you want to have a "for loop", again i'm not sure of your experience with code... so i'll put the rest of the code up and you can play around with it until you understand what's happening

Code:

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

using namespace std;

int main(int argc, char *argv[])
{

  int myarray[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  
  //print the array
  for(int i = 0; i < 10; i++)
    cout << myarray[i] << " ";
    
  //delete evens
  for(int i = 1; i < 10; i+=2)
    myarray[i] = 0;  // makes the evens 0

  cout << endl; // new line 
  
  //print the array again
  for(int i = 0; i < 10; i++)
    cout << myarray[i] << " ";
  
  cout << endl; // new line 
  
  system("PAUSE");	
  return 0;
}

hope this helps

>> hope this helps
you get a good grade on your homework.

Homework Policy

gg

ok, now it writes 0 in even numbers, but how to get them deleted. i could rewrite the array somehow? and why do I need (int argc, char *argv[]) and #include <stdlib.h>?

and one more question - what is deffensive programming?

>>how to get them deleted. i could rewrite the array somehow?

Yup, that's one way, and probably the easiest. You could also keep track of the number of elements in the array. Then start at index 0 and find and even number (or zero or whatever) and slide every number with a higher index than the current index to the left by 1 and decreasing the number of elements by 1, repeating the process until you run out of indexes to check. There are bound to be other ways as well.

argc is the number of arguments passed to main by the command line and the argv is an array of strings of size argc where each of those arguments is stored. Frequently, the default values of argc and argv are used by leaving the parenthesis blank.

stdlib is a library of commonly used functions. If you use iostream without the .h extension, you should probably use cstdlib, which is the updated version of stdlib.h just as iostream is the updated version of iostream.h

When I think of defensive programming I think of trying to include safegaurds to prevent the program from hanging or crashing from dumb mistakes that either I or the end user could make.

and I also need the code to write numbers in the array by itself not manually, but inthis way I have an error -parse error before'?
If I have to write the code in defensive programming, then what should I change? and what is the right way to write comments?
#include <iostream>

using namespace std;

int main()
{
int i, j, list[10]

for (i=0, i<10, i++){
list[j] = i;
};
for(i=0; i < 10; i++)
{
cout << list[i] << " ";

if(i != 0 && i % 2 != 0)
list[j++] = list[i];
}

cout << "\n\nList without even ones" << endl;

for(i=0; i < j; i++)
cout << list[i] << " ";
cout << endl;

system("PAUSE");
return 0;
}

it still says that there is an error... confused...
int main()
{
int i,list[10];
int j=0;

for (i=0, i<10, i++){
list[j] = i;
};

ok, now it works, but works wrong, it writes in wrong numbers.

Code:

for (i=0, i<10, i++){
list[j] = i;
};

; not needed, but not illegal.