Question about Null

Dec 9, 2014 at 4:31pm
When I try to compile this, an error comes up saying:

"a.cpp: In function ‘int main()’:
a.cpp:62:13: error: ‘null’ was not declared in this scope
srand(time(null))"

I am not sure how to declare null. I tried to initialize null with an integer but that produced a page long error message. Any suggestions?


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#include <iostream>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <ctime>

using namespace std; 

int findSmallestRemainingElement(int array[], int size, int index);

void swap(int array[], int first_index, int second_index); 

void sort (int array[], int size)
{
	for (int i = 0; i < 100; i++)
	{
		int index = findSmallestRemainingElement(array, size, i); 
		swap(array, i, index); 
	}
}

int findSmallestRemainingElement(int array[], int size, int index)
{
	int index_of_smallest_value = index; 
	for (int i = index + 1; i < size; i++)
	{
		if (array[i] < array[index_of_smallest_value])
		{
			index_of_smallest_value = i; 
		}
	}
	return index_of_smallest_value; 
}

void swap(int array[], int first_index, int second_index)
{
	int temp = array [first_index]; 
	array[first_index] = array[second_index];
	array[second_index] = temp; 
}

void displayArray(int array[], int size)
{
	cout << "{"; 
		for(int i = 0; i < size; i++)
		{
			if (i !=0)
			{
				cout << ", "; 
			}
			cout << array[i]; 
		}
		cout << "}"; 
}
int main() 
{
	int array[10]; 
	srand(time(null)); 
	for (int i = 0; i < 10; i++)
	{
		array[i] = rand() % 100; 
	}
	cout << "Original array: "; 
	displayArray(array, 10); 
	cout << '\n'; 
	sort(array, 10);
	cout << "Sorted array: ";
	displayArray(array, 10); 
	cout << '\n'; 
}
Dec 9, 2014 at 4:53pm
Here you go, null just needed to be in all caps for it to work.

srand(time(NULL));
Dec 10, 2014 at 2:58am
Hp of Legend. Thank you so much. You just saved me 25 minutes of trying to figure out what was wrong. You are amazing.
Last edited on Dec 10, 2014 at 2:59am
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