recursive way to print of an string by using pointer..

I want the clear explanation of how does these work

// recursive print of a string

void print(char* s)

{

if(*s==__char(0)___) return;

cout<<*s;

print(__s+1___);

}

void main(){ char a[6]="hello";

print(a);

}

// recursive reverse print of a string

void rev_print(char* s)

{

if(*s==__char(0)__) return;

___cout<<*s______;

___print(s+1)____;

}

void main()

{ char a[100];

cin>>a;

rev_print(a);

}