Software Learning Process


Hello World.......

High School/Jr.High
===================

10 PRINT "HELLO WORLD"
20 END


First year in College
=====================
program Hello(input, output)
begin
writeln('Hello World')
end.


Senior year in College
======================
(defun hello
(print
(cons 'Hello (list 'World))))

New professional
================
#include
void main(void)


char *message[] = {"Hello ", "World"};
int i;

for(i = 0; i < 2; ++i)
printf("%s", message[i]);
printf("\n");
}


Seasoned professional
=====================
#include
#include

class string

private:
int size;
char *ptr;

public:
string() : size(0), ptr(new char('\0')) {}

string(const string &s) : size(s.size)

ptr = new char[size + 1];
strcpy(ptr, s.ptr);
}

~string()

delete [] ptr;
}

friend ostream &operator <<(ostream &, const string ;
string &operator=(const char *);
};

ostream &operator<<(ostream &stream, const string &s)

return(stream << s.ptr);
}

string &string::operator=(const char *chrs)


if (this != &chrs)


delete [] ptr;
size = strlen(chrs);
ptr = new char[size + 1];
strcpy(ptr, chrs);
}
return(*this);
}

int main()

string str;

str = "Hello World";
cout << str << endl;

return(0);
}


Apprentice Hacker
===================
#!/usr/local/bin/perl
$msg="Hello, world.\n";
if ($#ARGV = 0)

while(defined($arg=shift(@ARGV)))
$outfilename = $arg;
open(FILE, "" . $outfilename) || die "Can't write

$arg: $!\n";
print (FILE $msg);
close(FILE) || die "Can't close $arg: $!\n";
}
} else

print ($msg);
}
1;


Experienced Hacker
===================
#include
#define S "Hello, World\n"
main(){exit(printf(S) == strlen(S) ? 0 : 1);}


Seasoned Hacker
===================
% cc -o a.out ~/src/misc/hw/hw.c
% a.out


Guru Hacker
===================
% cat
Hello, world.
^D


New Manager
===================
10 PRINT "HELLO WORLD"
20 END


Middle Manager
===================
mail -s "Hello, world." bob@b12
Bob, could you please write me a program that prints
"Hello, world."?

I need it by tomorrow.
^D


Senior Manager
===================
% zmail jim
I need a "Hello, world." program by this afternoon.


Chief Executive
===================
% letter
letter: Command not found.
% mail
To: ^X ^F ^C
% help mail
help: Command not found.
% damn!
!: Event unrecognized
% logout