Thread: Random

You could also write your own function to check duplicates if you don't have or don't know how to use the Standard Template Library.

Code:

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

int main(void){
	randomize();

	for (int i=0; i<5; ++i)
		cout << rand() % 11 <<" ";
	return 0;
}

Are my codes correct?! However, it shows error for the "randomize();". What can I do?? thx!!

Code:

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

inline void randomize(){
	srand((unsigned)time(NULL));
}

int main(void){
	
	int num1 = 0,num2 = 1;

	randomize();

	for (int i=0; i<5; ++i){
		num1 = rand() % 10;
		while (num1 != num2){
		cout << num1 <<" ";
		num2 = num1;
		}
	}
	cout <<endl;
	return 0;
}

I can use randomize now, but my program can't check out the repeated number. Pls help!! Thx!!~

How can I make a function to check the duplicates? What I wrote is:

Code:

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

inline void randomize(){
	srand((unsigned)time(NULL));
}

int main(void){
	
	int num1 = 0,num2 = 1;

	randomize();

	for (int i=0; i<5; ++i){
		num1 = rand() % 10;
		while (num1 != num2){
		cout << num1 <<" ";
		num2 = num1;
		}
	}
	cout <<endl;
	return 0;
}

However, it doesn't work. Can anyone tell me how to do it? Thanks!!~

int randomNumbers[5] = -1; //declare an array of ints and fill with number you know is not valid.

int index = 0; //to keep track of where you are in randomNumbers;

char found = 'n'; //a flag to indicate if current number found in randomNumbers

int i;

each time you generate a random number search the array to see if it is already there:

if randonNumber[0] is -1 then no valid numbers in randomNumbers yet and add current value to this spot.

else if randomNumber[0] not equal -1;
use a loop to look at all values in randomNumbers;
if current random number is same as any in randomNumbers then change found to 'y';
at end of loop check found. if found is 'n' then increment index and assign current random number to that spot in randomNumbers;

keep generating random numbers until index is 4, meaning there are 5 unique random numbers in randomNumbers.