arrays and functions

**dantestwin** · 07-08-2004

I'm working on a function that prints all the array elements that are between 2 values in the array. I keep getting these errors in my function call and I dont know why since I declared them in the prototype. I'm a bit shaky when it comes to deal with arrays in functions. The for loop I have going to print the elements in between the 2 values looks very dry and of course is not done. Do i have to pass in an array as a parameter because I'm working with an array? ugg, this is so frustrating. Thank you for your time.

Code:

   #include <iostream>
using namespace std;
void print (int x,int y );//prototype
int main()
{
 
 const int size=10;
int a[size]={1,2,3,4,5,6,7,8,9,10};

 cout<<"The elements printed are"<<print(x,y);//call

  return 0;
 
}

 void print(int x, int y) //print out all  elements between 2 given parameters
 {

	 for (int i=x; i<y; i++)  //not done
		 cout<<i;

 }

**dantestwin** · 07-08-2004

Sorry, forgot to include the errors.

Code:

 error C2065: 'x' : undeclared identifier
 error C2065: 'y' : undeclared identifier

**Salem** · 07-08-2004

Try

cout<<"The elements printed are"<<print(0,10);//call

**dantestwin** · 07-08-2004

Then i get this error:

Code:

binary '<<' : no operator defined which takes a right-hand operand of type 'void' (or there is no acceptable conversion)

Plus the fact that the function has to work for any 2 given parameters.

**Prelude** · 07-08-2004

>binary '<<' : no operator defined which takes a right-hand operand of type 'void'
print returns a void type, so it can't be printed. You'll want to split up the calls:

Code:

cout<<"The elements printed are ";
print(0, 10);

>Plus the fact that the function has to work for any 2 given parameters.
It will, but you need to get those values somehow first. The easiest way is to hardcode them, but I imagine you'll want to prompt for user input.

**dantestwin** · 07-08-2004

Ok that problem with the errors has been solved, thanks prelude.

The program runs fine but there is one logic error. When I enter 2 numbers, it always prints out the range of numbers in between the 2 in the array but also the first number entered. I tried changing the condition in the for loop but I get tons of errors as a result. If anybody can assist me with excluding the first parameter in the range without causing tons of errors, I would be ever so grateful.

Code:

     #include <iostream>
using namespace std;
void print (int x,int y );//prototype
int main()
{
	 
 int x;
 int y;
 const int size=10;
int a[size]={1,2,3,4,5,6,7,8,9,10};

 cout<<"Enter 2 values: ";
 cin>>x>>y;
 cout<<"The elements printed between"<<x<<"and"<<y<<"are";
	 print(x,y);//call

  return 0;
 
}

 void print(int x, int y) //print out all  elements between 2 given parameters
 {

	 for (int i=x; i<y; i++) //can't exclude x from being printed
		 cout<<i;

 }

**Prelude** · 07-08-2004

I think you're confused about what you're doing and what you want to do. What you want to do is use x and y as indices for printing out the elements of the array. What you're doing is echoing all numbers between x and y. This is what you want:

Code:

#include <iostream>

using namespace std;

void print(int array[], int x, int y);

int
main()
{
  int array[] = {1,2,3,4,5,6,7,8,9,10};
  int x, y;

  cout<<"Enter two numbers: ";
  cin>> x >> y;
  cout<<"The elements in [x,y) are: ";
  print(array, x, y);
  cout<<endl;
}

void
print(
  int array[],
  int x,
  int y
  )
{
  cout<< array[x];
  while (++x != y) {
    cout<<", "<< array[x];
  }
}

**dantestwin** · 07-08-2004

That's pretty good code, Prelude but when I run it, the Y parameter gets printed out also. All i want is this. If the user enters the numbers, 3 and 9. I want my code to print out, 4, 5, 6, 7, 8. Thats it. With my original code I kept printing out the 3.

**Prelude** · 07-08-2004

>but when I run it, the Y parameter gets printed out also.
No, it doesn't. In C++, array indices begin with 0. So the 9th element is 10, which is not printed when you give the input 3 9. So my code will give you the correct answer if you want every element from array[x] to array[y - 1] including array[y - 1] printed.

>I want my code to print out, 4, 5, 6, 7, 8. Thats it.
Then you subtract 1 from the condition:

Code:

#include <iostream>

using namespace std;

void print(int array[], int x, int y);

int
main()
{
  int array[] = {1,2,3,4,5,6,7,8,9,10};
  int x, y;

  cout<<"Enter two numbers: ";
  cin>> x >> y;
  cout<<"The elements in [x,y) are: ";
  print(array, x, y);
  cout<<endl;
}

void
print(
  int array[],
  int x,
  int y
  )
{
  cout<< array[x];
  while (++x != y - 1) {
    cout<<", "<< array[x];
  }
}

**dantestwin** · 07-08-2004

You're a genius Prelude! Thanks.

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