Thread: Keep getting erron messege, not sure how to fix it!

srand is funstion which does not returns value - it should be called once to randomize your sequence of random values

rand is function that returns a random value. it does not accept parameters...

srand() is to seed the random number generator so it does not always generate the same sequence of numbers. Use it once before you call rand() like this:

Code:

#include <ctime>
srand(time(NULL));

rand() is the function that actually returns a random number.

You don't simply want to replace srand with rand: you want to use both.

As MK27 stated, you call srand once to seed the random number generator, then use rand in your
loop to get your random numbers. Calling rand without first calling srand, AFAIK, implicitly calls srand(1).

Code:

 
#include <iostream> 
#include <vector> 
#include <ctime> 
#include <cstdlib>  

int main(int argc, char* argv[]) {  
	unsigned int i = 0; // Iterator variable  
	int num = 0; // Random number  
	std::vector<int> evens; // Vector for even numbers  
	std::vector<int> odds; // Vector for odd numbers   

	srand(time(NULL)); // Seed random number generator   

	// Fill vectors with random numbers  
	for(i = 0; i < 100; i++) {   
		num = rand();   
		if ((num % 2) == 0)    
			evens.push_back(num);   
		else    
			odds.push_back(num);  
	}   

	// Display even numbers  
	std::cout << "Displaying even numbers:" << std::endl;  
	for (i = 0; i < evens.size(); i++) {   
		if ((i % 5) == 0)    
			std::cout << std::endl;   
		std::cout << evens[i] << " ";  
	}   

	std::cout << std::endl << std::endl;    
	
	// Display odd numbers  
	std::cout << "Displaying odd numbers:" << std::endl;  
	for (i = 0; i < odds.size(); i++) {   
		if ((i % 5) == 0)    
			std::cout << std::endl;   
		std::cout << odds[i] << " ";  
	}   

	return 0; 
}