Thread: Empty Array

You don't have to have it empty. Just fill it up and keep track of your last entry (assuming you aren't using the entire thing). There is no "empty" state in C. You could specify a value as "empty" and check that spot to see if it equals "empty", but there is no such thing as an empty array.


Quzah.

Use a vector of strings like this:

Code:

std::vector<std::string> myStrings;

std::string tmp;
do {
  std::getline(std::cin, tmp, '\n');
  myStrings.push_back(tmp);
} while(tmp != "stop")
myStrings.pop_back();

God, sorry. I forgot I was in the C forum. Nevermind my post.

> and he entered 20 how would i tell the array to be that big ?
There's no such thing as an expanding array in C.

Either you have

Code:

int arr[100];
int numEntries = 0;
printf( "Enter up to 100 numbers\n" );
for ( i = 0 ; i < 100 ; i++ ) {
  if ( scanf("%d",&arr[i]) != 1 ) {  // not the best input routine
    // end of data (somehow)
    numEntries =  i;
    break;
  }
}

Or you could dynamically extend an allocated pointer by using realloc.

Linked list?

The closest you can get is realloc.


Quzah.

Just declare an array (of some size).
Then ask the user "How many numbers do you want to input?"

If that's bigger than your array size, just print a message and exit.

If the number of elements is input first, you don't need the realloc() stuff. You can go with simple malloc(). As long as you've learned pointers, that's enough.

If you haven't learned pointers, either go with Salem's approach or complain to the teacher.

ok i think i figured out a way around it...i ask the user for how many numbers it wants to enter...then pass that number to a function and create an array

however i get this error:
constant expression required in function meanArray

Code:

#include <stdio.h>

/*
In statistics, the mode of a set of values is the value which occurs most often or with the 
greatest frequency. Write a function that accepts the following arguments:
•	An array of integers
•	An integer that indicates the number of elements in the array
*/

int meanArray(int arrayNum);

int main()
{
	int num;

	printf("How many numbers do you want to enter ? ");

	scanf("%i", &num);

	meanArray(num);

	return 0;
}

int meanArray(int arrayNum)
{
	
	int makeArray[arrayNum];

	return 0;
}