CODEWITHSUNDEEP
c++loopsrandom
Liz
Liz

Reputation: 41

How do I randomize these numbers?

So my homework assignment is to create a looping function to print only even numbers from 0 – 200. I need to create 100 random and even numbers(only 10 numbers can print per line). I'm having trouble randomizing the numbers. This is what I have so far: 

// Loop from 0 to 200 
for (i = 2, j = 1; i <= 200; i++, j++)
{
    // Print even numbers(divisible by 2)
    if (i % 2 == 0)
    {
        cout << i;
    }

    // Create new line after printing 10 numbers
    if (j == 20)
    {
        j = 0;
        ofs << '\n';
    }
}

Upvotes: 2

Views: 122

Answers (3)

Hamza Anis
Hamza Anis

Reputation: 2565

#include <stdio.h>      /* printf, scanf, puts, NULL */
#include <stdlib.h>     /* srand, rand */
#include <time.h>       
int main()
{ 
    srand (time(NULL));
    int even = rand() % 200;
    if (even % 2 == 0)
    {
        cout<<even;
    }
}

Upvotes: 2

ParadobC2
ParadobC2

Reputation: 72

Apart from that, your code is a little off the way. Here are some things that may be confusing to other coders (.. anyways if you feel comfortable with your style that's really ok)

"for (i = 2, j = 1; i <= 200; i++, j++)" 2 Variables are a little bit wierd, try to use only one variable. .. Just make it something like this:

int j = 1;
for (i = 2; i <= 200; i++) {
j++;

//Code

if (j == 20) {
   j = 0; //etc.
}

}

Beside that "J" looks familliar to "I" so that could confuse others.. try to call it "count", that's pretty standard.

Upvotes: 0

Archie
Archie

Reputation: 2672

Here is some quick code that prints 100 even numbers [0..200] in a random order without repeating them:

#define PRIME       7879    /* Some big prime number (>> 100)       */
#define NUMS        100     /* Number of values to process          */
#define PRINT_GROUP 10      /* Number of values printed on a line   */

int main()
{
    int number = rand() % NUMS;
    int i;
    for (i = 0; i < NUMS; i++) {
        printf("%d%c", 2*number, (i + 1) % PRINT_GROUP == 0 ? '\n' : ' ');
        number = (number + PRIME) % NUMS;
    }
    return 0;
}

Upvotes: 1

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