If you want to search a string for a substring which starts with "abc" and ends with "xyz". then do this:
(1) write a function ( I'll call it fun_a( ) ), which looks for a specified character sequence, and returns the position of the first character where it occurs, or -1 if it doesn't occur anywhere.
int fun_a( char* string, char* substring )
{
}
(2) write another function fun_b( ) which does this.
int fun_b ( char* string, char* substring1, char* substring2 )
{
int p= fun_a( string, substring1 );
int q = fun_a( string, substring2 );
if ( p >= 0 && q >=0 && q>p ) return p ;
else return -1 ;
}