Converting kilometers to miles in loop problem

Hey guys, I have a homework question to convert kilometers to miles, then loop the program until the input is zero or negative.
please help me find any errors so that it can run.

Code:

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#include <stdio.h>
#include <math.h>
int main (void)

{
        double kilometres, miles, counter;
       
        scanf("%lf", &kilometres);
        if (kilometres>0)
                {
                miles=kilometres*0.6214;
                printf("Your distance is %lf kilometres = %lf miles", kilometres, miles);
                }
               
        else
       
}

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Any help would be appreciated thanks!!

Code:

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while(1)
{
 scanf("%lf", &kilometres);
  if (kilometres>0)
  {
  miles=kilometres*0.6214;
  printf("Your distance is %lf kilometres = %lf miles", kilometres, miles);
  }
  else break;
}

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Thanks alot