Design and development help in C++ text game

[nemisis]

Hi Everyone I have am doing an object oriented C++ program and I have no idea as to how start it............. ....

This program prints a motion verb ( fly, run, swim, crawl, walk, or roll ), waits for a second,
then prints the name of an entity and repeats the verb (for example: fly ..1s.. pigeon fly!.. ).
The player has ½ second to type ‘y’ for yes or ‘n’ for no. (case insensitive)
- If the answer is correct, the player scores, if incorrect, or if there was no answer within the ½ second, the
player looses a point. When correct, all the motions the entity can perform are printed.

- When wrong, Ka..BOOM! is printed instead.

The default number of questions per player is 20, but the number can be changed by passing a different
number on the command line when starting the program.


At the end of the run the player’s score (and the score of previous players if there were any) is printed, the
question: “Another player (Y/N): “ is asked. The game exits if ‘n’ is typed.

The output should look something like this:-

Player 1 starting.
You must answer with the letter ‘y’ for YES, or ‘n’ for NO.
Press [Enter] when ready to start:

1 – fly pigeon fly!.. y
- I walk - I fly
2 – swim Wheelbarrow swim.. n
- I roll
3 – crawl ball crawl!..
Ka...BOOM!
4 – fly plane fly!.. y
- I roll - I fly.
5 – run boat run!.. n
- I roll.
6 – walk engine walk!..
Ka..BOOM!
7 – roll stone roll!.. y
- I roll.
. . .
16- crawl time crawl!.. y
- I crawl - I fly.
17- swim goose swim!.. n
Ka..BOOM!
18- run lizard run!.. y
- I run - I crawl.
19- run nose run.. y
- I run
20- fly goose fly!.. y
- fly - I walk – I run – I swim.

Player 1 *** score: 16 ***

Well done! Start another player (Y or N)? y

Player 2 starting
You must answer with the letter ‘y’ for YES, or ‘n’ for NO.
Press [Enter] when ready to start:

1 – crawl giraffe crawl!.. y
Ka..BOOM!

I am not that good at coding so i tried and made an overview of what the main driver should look like


main{
start_function( a,b)
{
check here wherther the player is old or new------>Connector

where a = value of yes or no, taken by cin>>
if the vaue is yes....
}
you are back in main >>>here

now start the for...while/Do...while[(condition for 1/2 min)& this shld take care of the initial 30 seconds also]
{
call function2(loop for 20 questions)
else if right answer add a point
Also call a function to print what the object does (for ball, it will be I ROLL)

keep adding ( + or -)points in a variable

End for loop of questions
}

display final score
ask to replay ------------>connector
}


But as said above I have no idea on the coding part of the whole program and would like some help here please

Also apart from this can anyone suggest a good compiler, I use Visual Basic C++ if thats good

[nemisis]

ok i ll go through the stuff till u get back then i have to sleep. see ya l8r

[nemisis]

Get rid of the *. Make it return a 'string' not a 'string*'.

doesnt work i have to change it in all files ie. motion.h, motion.cc and flymotion.h and after doing that too i am getting more errors which is way out of my understanding!! !

EDIT: P.S. If you want, you can take a look at a preliminary document I am writing regarding Parsing in C++ here. It is in review so that is why it is located in the Editors Corner.

Again, i am not that familiar with parsing so i will have a look 2morrow as soon as i am out of bed since nothing is getting inside at this time of the night. Good night


ps- if u want i can post the errors i get when i change to string from string* , i didnt as there are 4-5 of them and i got confused lookin at them hence put back string*.

[AdrianH]

Ok, when you state a type (whether it is a return type, parameter type or variable type) there are three ways of declaring it in C++, by value, by reference and by indirection (I'm not sure if indirection is the standard term though).

By value means that you have an object. If you initialise an object by another object a constructor is invoked to initialise the object. If is initialised with another object of the same type the copy constructor is invoked to copy the object. The copy constructor is just a special constructor that takes a const type reference. More on that type later. E.g.

// Takes a string by value, constructor is invoked in this case (copy 
// constructor if passed a string).
// 
// Returns a string by value, copy constructor is invoked.
string fn1(string param)
{
  return param;
}
 
int main()
{
  string var1("hello");  // Constructor to init var1 to contain "hello".
 
  string var2 = "hello"; // Even though this looks like an assignment, it is 
                         // still an initialisation, so the same constructor
                         // as above is called.
 
  string var2(var1);     // var1 is a string, so the copy constructor is 
                         // invoked.
 
  string returnValue 
    = fn1(var1);  // fn1 is passed var1 which is a string.  param is the same 
                  // type, thus to initialise param, the copy constructor is
                  // invoked.  This is known as passing by value.
                  //
                  // fn1 returns a string, param is also a string, the return
                  // value is initialised using the copy constructor.
  return 0;
}
 

By reference means that you are borrowing the actual object. Thus, if you modify it (and it is not a const type reference), the original object will be modified. Behind the scenes, this may look like a const pointer (see by indirection). It is almost always initialised with an actual object.

void fn2(string& param1, string const & param2)
{
  param1="bye";  // Not invoking constructor, invoking the assignment operator.
                 // If no assignment operator function defined, it will destroy
                 // var1 and invoke the copy constructor on the memory space of
                 // var1.
 
  param2="lala"; // Invalid operation, param2 is a constant, thus cannot be 
                 // changed.  Comment out to get to compile.
}
 
int main()
{
  string var1("hello");  // Constructor to init var1 to contain "hello".
  string var2("bye-bye");
  string& var3(var1);    // Init to reference var1 (also known as an alias)
  string& var4 = var2;   // Init to reference var2
  fn2(var1, var2);
 
  cout << "var1: " << var1 << endl; // outputs "var1: bye"
  cout << "var2: " << var2 << endl; // outputs "var2: bye-bye"
  cout << "var3: " << var3 << endl; // outputs "var3: bye"
  cout << "var4: " << var4 << endl; // outputs "var4: bye-bye"
 
  return 0;
}
 

By indirection means that you indirectly point at the object you are referring to. To get access to the object, you either use the dereference operator (‘*’), or the member selection operator (‘->’) which is only valid for non-base types. The value of the pointer can be any value between 0 (usually called NULL) and the maximum addressable space value.

void fn3(string* param1, string const * param2)
  if (param1 == NULL) {
    cout << "param1 is NULL" << endl;
  }
  else {
    cout << "param1 points at string '" << *param1 
         << "'.  Its length is " << param1->length()
         << ".  Adding ' there' to it." << endl;
    *param1 += " there";
  }
 
  if (param2 == NULL) {
    cout << "param2 is NULL" << endl;
  }
  else {
    cout << "param2 points at string '" << *param2 
         << "'.  Its length is " << (*param1).length() // also valid
         << ".  Cannot add ' there' to it." << endl;
    //*param2 += " there";  // INVALID since pointing at a const value.
  }
}
 
int main()
{
  string var1("hello");
  string var2("bye-bye");
  string* var3(&var1);   // Init to point at var1
  string* var4 = &var2;  // Init to point at var2
  fn3(var1, var2);
 
  cout << "var1: " << var1 << endl; // outputs "var1: bye"
  cout << "var2: " << var2 << endl; // outputs "var2: bye-bye"
  cout << "var3: " << var3 << endl; // outputs "var3: bye"
  cout << "var4: " << var4 << endl; // outputs "var4: bye-bye"
 
  return 0;
}
 

NOTE: there are no constructors that will convert a string* to a string (although one could theoretically be made, it makes little sense and could result in inadvertent conversions) or a string to a string* (there is no automated way to make such a conversion).

I hope that what I have written will help point you in understanding what you are doing wrong.


Adrian

[nemisis]

ok I changed string* to string......... ........ now i get these errors


flymotion.cc: In static member function 'static FlMotion* FlyMotion::inst ance()':
flymotion.cc:li ne 20:error: cannot allocate an object of type 'flymotion'
flymotion.cc:li ne 20:error: because the following virtual functions are abstract:
Motion.h:line 17:error: virtual bool Motion::contain s(std::string) const

[AdrianH]

ok I changed string* to string......... ........ now i get these errors


flymotion.cc: In static member function 'static FlMotion* FlyMotion::inst ance()':
flymotion.cc:li ne 20:error: cannot allocate an object of type 'flymotion'
flymotion.cc:li ne 20:error: because the following virtual functions are abstract:
Motion.h:line 17:error: virtual bool Motion::contain s(std::string) const

You didn't declare and define bool FIMotion::conta ins(string) const function.

Won't be in for the rest of the day.


Adrian

[nemisis]

Won't be in for the rest of the day.


Adrian

hhmmmmmm just when i need u............. o well i aint sleeping for 48 hrs so whenever u come back i ll still be here

[Savage]

hhmmmmmm just when i need u............. o well i aint sleeping for 48 hrs so whenever u come back i ll still be here

What a irony,eh?

PS:Subscribing

Savage

[nemisis]

What a irony,eh?

PS:Subscribing

Savage

better get to work then i was slackin cuz i thought adrian wasnt around, well next post in an hr or so............. ..

[nemisis]

You didn't declare and define bool FIMotion::conta ins(string) const function.

the bool FlyMotion::cont ains(string) is declared in Motion.h line 17 but i cant figure out what to define in it?? any suggestions??

[nemisis]

#ifndef MOTION_H
#define MOTION_H
 
#include <iostream>
#include <string>
 
using namespace std;
 
class Motion
{
    friend ostream &operator << (ostream &out, const Motion &m);
 
    public:
        Motion();
        virtual ~Motion(){};
        virtual string toString() const = 0;
        virtual bool contains(const string key) const = 0;
};
 
 
#endif

#include <iostream>
#include <sstream>
#include <string>
 
#include "Motion.h"
 
ostream &operator << (ostream &out, const Motion &m)
{
    out << "- I " << m.toString();
    return out;
}

#ifndef FLYMOTION_H
#define FLYMOTION_H
 
#include <iostream>
#include <string>
 
using namespace std;
 
#include "Motion.h"
 
class FlyMotion : public Motion
{
    public:
        static FlyMotion* instance();
        virtual string toString() const;
        virtual bool contains(const string key) const;
 
    //protected:
        FlyMotion();
        FlyMotion(const FlyMotion&);
        ~FlyMotion(){};
 
    private:
        static FlyMotion *inst;
     // return &inst;
};
 
 
#endif

#include <iostream>
#include <sstream>
#include <string>
 
#include "FlyMotion.h"
 
using namespace std;
 
FlyMotion* FlyMotion::inst = 0;
 
FlyMotion::FlyMotion()
{
    inst = 0;
}
 
FlyMotion* FlyMotion::instance()
{
    if(inst == 0)
    {
        inst = new FlyMotion;
    }
    return inst;
}
 
 
string FlyMotion::toString() const 
{
  ostringstream outStr;
 
   outStr << Motion::toString() << "fly " << flush;
 
return outStr.str();
}        

------ Build started: Project: Project1, Configuration: Debug Win32 ------
Linking...

FlyMotion.obj : error LNK2019: unresolved external symbol "public: __thiscall Motion::Motion( void)" (??0Motion@@QAE @XZ) referenced in function "public: __thiscall FlyMotion::FlyM otion(void)" (??0FlyMotion@@ QAE@XZ)


FlyMotion.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall FlyMotion::cont ains(class std::basic_stri ng<char,struct std::char_trait s<char>,class std::allocator< char> >)const " (?contains@FlyM otion@@UBE_NV?$ basic_string@DU ?$char_traits@D @std@@V?$alloca tor@D@2@@std@@@ Z)


FlyMotion.obj : error LNK2019: unresolved external symbol "public: virtual class std::basic_stri ng<char,struct std::char_trait s<char>,class std::allocator< char> > __thiscall Motion::toStrin g(void)const " (?toString@Moti on@@UBE?AV?$bas ic_string@DU?$c har_traits@D@st d@@V?$allocator @D@2@@std@@XZ) referenced in function "public: virtual class std::basic_stri ng<char,struct std::char_trait s<char>,class std::allocator< char> > __thiscall
FlyMotion::toSt ring(void)const " (?toString@FlyM otion@@UBE?AV?$ basic_string@DU ?$char_traits@D @std@@V?$alloca tor@D@2@@std@@X Z)


LIBCMT.lib(crt0 .obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStar tup


C:\Documents and Settings\Admin\ Desktop\c++\Pro ject1\Debug\Pro ject1.exe : fatal error LNK1120: 4 unresolved externals


Build log was saved at "file://c:\Documents and Settings\Admin\ Desktop\c++\Pro ject1\Project1\ Debug\BuildLog. htm"


Project1 - 5 error(s), 0 warning(s)


========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========