/*********Reverse Root***********/
/*
Program to input a stream of NO:s and beginning from the end of the stream , print their square root

--math.h is not linked by default in gcc , you have to link it by option -lm , in command . math.h is in libm , only libc functions are linked by default
--use strtod() to convert from string to double , stdlib.h


*/




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

/*function to reverse a string*/
void strrev(char string[256])
{
 char reverse[256];
 int i,j;
 i=strlen(string);

 for (j=i-1;j>=0;j--)
  {
    reverse[i-1-j]=string[j];
  }
  reverse[i]='\0';
  strcpy(string,reverse);
}


int main(void)
{

 int k=0,i=0,j,different=0,start=0;
 int c;
 char stream[256];
 char num[256];
 char copy[256];
 double number;
 while((c=getchar())!=EOF)
  {
   stream[i]=c;
   j=i;
   i++;
  }

 for (k=j;k>=0;k--)
  {
   if(isdigit(stream[k])!=0)
     {
       if(isdigit(stream[k-1])!=0)
        {
          num[start]=stream[k];
          start++;
        }
       else
        {
          num[start]=stream[k];
          num[start+1]='\0';
//          printf("%s\n",num);
          strrev(num);
//          printf("%s\n",num);
          strcpy(copy,num);
          number=strtod(copy,NULL);
          printf("%0.4f\n",sqrt(number));
          start=0;

        }
     }
  }

  return 0;

}

Can anybody tell me why does it gives wrong answer...?
Any help would be highly appreciated..