Thread: Need help: sorting random numbers rand() to odd and even in C

Originally Posted by kasuka

Hi guys, thanks for replies. Basically what ive been tryin to achieve is to generate 10,000 numbers
thats why im using

Code:

  for(i = 0; i <= 10; i++)
    {
       ran_num = (10.0*rand()/(RAND_MAX+1.0));
       arr[ran_num]++;
     }

If you want to generate 10,000 random ints in an array you don't do it that way, you're going to run into all kinds of array bounds errors and parts of the array will be left unused...

Try it like this...

Code:

int array = malloc(10000 * sizeof(int));  // it's too big for the stack.
int i;

for (i = 0; i < 10000; i++)
  array[i] = rand();

... see how easy that is?

and store it to the array and then divide them to even and odd

Code:

    if (arr[ran_num] %2 == 0)
       {
          printf("%d\n", arr[ran_num]);
          eve_num++;
       }
    else
       {
          printf("%d\n", arr[ran_num]);
          odd_num++;
       }
 
     printf("Even No.s : %d\n", eve_num);
     printf("Odd No.s  : %d\n", odd_num);

i know the logic but im consfused to write it in codes

This part of your code is basically ok... except for the way you pick stuff out of the array...

Code:

int odd_nums = 0;
int even_nums = 0;

for (i = 0; i < 10000; i++)
  if (array[i] & 1)   // true for odd, false for even
    odd_nums++;   
  else
    even_nums++;

  printf("/nThere were %d odd numbers and %d even numbrers", odd_nums, even_nums);

Again... very easy to do.

The trick is to think like the computer... little tiny steps, in strict order...

Originally Posted by CommonTater

Please don't just haul off and post complete solutions like that. You may put a smile on the OP's face but you totally deny them any chance of learning anything about programming. He's learned nothing of process or procedure... all he really knows from you is how to copy and past (scoop and poop) code for his own homework...

Plus there are errors in your code.

Point is taken. I will keep your advice in mind, for my future posts.

Thank you so much guys ... im finally getting the idea here ..i will try to code it once more see whats gonna happen.

and oops i forgot to add ... i was really confused about this stuff because its not just random numbers i mean ... i have to set the random numbers from No.s 0-9. Thats why i have arr[10]. So generate 10k numbers (which can be 0, 1,2,..9) and then divide these numbers to Odd and Even. On my previous code .. it can generate 10k random numbers from 0 - 9. Ive been trying to separate the Odd and even numbers and get the sum (of how many odd numbers. of how many even numbers)

If there's a limit on your rand() numbers, you do that like this...

Code:

#define LIMIT 10

int array = malloc(10000 * sizeof(int));  // it's too big for the stack.
int i;

for (i = 0; i < 10000; i++)
  array[i] = rand() % LIMIT;

Look up the modulous operator ( % ) in your C documentation.

The thing is, as I mentioned before, you need to stop guessing...
Analyse the problem, Plan a solution, Write the code, Test your code.