Checking for repeat values

techrolla · 12-08-2003, 09:27 PM

Im wondering how, using for loops, to generate a small array [5] of integers in c++ by going through the array and generating random numbers but making sure that they arn't already in the array. Im looking for a simple, no pointer, for, solution, any suggestions would be greatly appreciated, thanks.

ToniT · 12-08-2003, 09:48 PM

Code:

// Warning: never tested, just writen in the fly.
int inTheArray(int a[],int value,int len) {
for(int i=0;i<len;i++) if(a[i]==value) return 1;
return 0;
}

int foo[5];
for(int i=0;i<5;i++) {
   int number;
   do{
       number=random();
   } while(inTheArray(foo,number,i));
   foo[i]=number;
}

techrolla · 12-08-2003, 09:58 PM

Thank you for replying, I had though of that before, but what I need is a purely for looping check without functions, I should have stated that. Thanks for taking the time though

Something like:

Code:

for(i=0; i < 5; i++)
{
    for(k=2; k < i; k++)
    {
         if(values[k] == values[k-1])
                values[k] = round(10*rand()); //dont mind if these functions are incorrect right now, I can fix that later
   }
}

The only problem is that there are repeated values still. Thanks

deiussum · 12-09-2003, 08:24 AM

So you are saying you can't figure out how to take ToniT's code and modify it so that it doesn't use a function? You could put the code he has in his function within the for loop like so:

Code:

// Warning: never tested, just writen in the fly.
int foo[5];
for(int i=0;i<5;i++) {
   int number;
   int inTheArray; 
   do {
      number=random();
      inTheArray = 0;
      for(int j=0;j<i;j++) {
          if (foo[j]==number) {
             inTheArray = 1;
             break;
         }
      }
   } while(inTheArray);
   foo[i]=number;
}

techrolla · 12-09-2003, 08:41 PM

Thanks for the help and replies, it wasn't that I didn't know how to change it, I was actually looking for something a little different, like a very primitive array search, probably slower than these examples, but it works. Actually, its very similar to the other ones, but a little different. I figured it out, its kinda like a bubble search. sorry this one is in pascal.

Code:

  
                      for i:=0 to 5 do
                      begin
                           num := random(15);
                           for k:=0 to i-1 do
                           begin
                                lotNumbers[i] := num;
                                if lotNumbers[i] = lotNumbers[k] then
                                begin
                                     num := random(15);
                                     k := 0;
                                     i:=i-1;
                                end;
                           end;
                     end;

C++: This doesnt seem to work, but its the basic Idea:
EDIT: It actually does work, I had a wierd print out: '

Code:

#include <iostream.h>
for(i=0; i < 5; i++)
	{
		num = rand();
		if(i > 0)
			for(k=0; k < i-1; k++)
			{
				vs[i] = num;
				if(vs[i] == vs[k])
				{
					num = rand();
					k = 0;
					i = i-1;
				}
			}
		else
			vs[i] = rand();
	}