Concatenate two strings without using strcat: C source code

"
#include<stdio.h>
#include<conio.h>

void main()
{
 char s1[30],s2[30],s3[30];
 char *x,*y;
 int i=0;
 scanf("%s %s",s1,s2);
 x=s1;
 //first method given in comments(this method uses the third string)
/* while(*x!='\0')
 {
  *(s3+i)=*x;
  x++;i++;
  }
  x=s2;
   while(*x!='\0')
 {
  *(s3+i)=*x;
  x++;i++;
  }
  *(s3+i)='\0';
  printf("%s",s3);
  */
  //second method(uses no external string)
 while(*x!='\0')
 {
  x++;
  }
  y=s2;
  while(*y!='\0')
  {
   *x=*y;
   x++;y++;
   }
   *x='\0';
   printf("%s",s1);
 getch();
}
"