generating 10 unique random numbers in C

Code:

---

#include<stdio.h>
#include<stdlib.h>

int main()
{
    int i=0,j=0,n=0,a[10],flag=-1;
    for(i=0;i<10;i++)
    {
        a[i]=-1;
    }
    while(i<10)
    {
        n=rand()&#37;10;
        for(j=0;j<10;j++)
        {
              if(n==a[j])
              {
                  flag=0;
                  break;
              }
              else
              {
                  flag=1;
              }
        }
        if(flag==1)
        {
              a[i]=n;
              i++;
          } 
    }
    for(i=0;i<10;i++)
    {
        printf("%d\n",a[i]);
    } 
}

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when i compile and run the above code I get -1.
it should generate 10 unique random numbers between 10, but it does not...

i use gcc this is the output

Code:

---

$ gcc random.c
$ ./a.out
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1

---

after the first for loop the "i" variable equals 10, so the while loop never run.
By the way, if you had stepped through your code with the debugger you'd have seen it immediately.

its really pathetic of me...

please mods...lock and delete this thread...

i didnt set i=0

Quote:

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Originally Posted by superbonzo

after the first for loop the "i" variable equals 10, so the while loop never run.
By the way, if you had stepped through your code with the debugger you'd have seen it immediately.

---

yeah i did and i found out...it was super-lame of me to even ask...:(

Quote:

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Originally Posted by creeping death

yeah i did and i found out...it was super-lame of me to even ask...:(

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Note random_shuffle in the C++ standard.

Code:

---

#include<stdio.h>
#include<stdlib.h>

int main()
{
    int i=0,j=0,n=0,a[10],flag=1;
    for(i=0;i<10;i++)
    {
        a[i]=-1;
    }
    i = 0;
    srand(time(NULL));
    while(i<10)
    {
        n=rand()%10;
        flag = 1;
        for(j=0;j<10;j++)
        {
              if(n==a[j])
              {
                  flag=0;
                  break;
              }
        }

        if(flag==1)
        {
              a[i]=n;
              i++;
          }
    }
    for(i=0;i<10;i++)
    {
        printf("%d\n",a[i]);
    }
}

---

You'll probably want to call srand in there too.