C program to Concatenate two strings

\* C program to Concatenate two strings *\

# include < stdio.h >
# include < conio.h >
int   main( )
{

char s1[100], s2[100], i, j ;
printf("\n Enter first string: ") ;
scanf("%s", s1) ;
printf(" Enter second string: ") ;
scanf("%s", s2) ;
for(i = 0; s1[i] != '\0'; ++i) ;
for(j = 0; s2[j] != '\0'; ++j, ++i)
{
      s1[i] = s2[j] ;
}
s1[i] = '\0' ;
printf(" After concatenation: %s", s1) ;
return 0 ;

}