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SSales Tax Calculator Class

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Join Date: Sep 2009

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serdengil

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SSales Tax Calculator Class

Sep 15th, 2009

Hey guys,

I do have a main function and need to write the class. I just need to where should I start. I am a new in C++ but the prof. asked us to write the class code of this calculator. He already gave the main function and the purpose of the class is an
HP calculator has a screen and a push down stack that can hold up to 20 entries. The calculations of multiplication addition subtraction and division are all performed. if more then 20 entries are pushed, it will crash.

[code.c++]

int main(){
StCalc a;
a.enter(2); //screen has 2
a.push() .enter(3); //2 on stack screen has 3
a.push() .add() .pop(); // 2 3 on stack, add, pop to screen which has 5
cout<<"Expect StCalc (5): "<<a<<endl; // test "<<"
cout<<"Expect 5: "<<a.getScreen()<<endl; //test getScreen()
a.push() .enter(4); //5 on stack 4 on screen
cout<<"Expect StCalc (20): "<<a.push() .mul() .pop<<endl;
a.push() .enter(8); //stack has 20 screen has 8
cout<<"Expect StCalc(2.5): '<<a.push() .sub() .pop() <<endl;
a.push() .enter(3); //2.5 on stack, 3 on screen
cout<<"Expect StCalc(-0.5): <<a.push() .sub() .pop()<<endl;
a<<42; //test overload "<<", which stores 42 on screen
cout<< "expect 10: ""<<(a==42)<<(==3)<<endl; //test boolen ==
cout<<"Expect StCalc (42): "<<a<<endl;
a.enter(3);
a+=2; //test overloaded +=
cout<<"Expect StCalc(5): "<<a<<endl;
a.push() .enter(0);
//a.push() div(); //should crash
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
}

void check(bool b, char *mess, int line, char *filename) {
if(!b){
cerr<<"ERROR(line "<<line<<" in file '""<<filename<<"'): "<<mess<<endl;
exit(1);
}
}

/* the OUTPUT

Expect StCalc (5): StCalc (5)
Expect 5: 5
Expect StCalc (20)

tCalc(20)
Expect StCalc (2.5): StCalc(2.5)
Expect StCalc (-0.5): StCalc (-0.5)
Expect 10: 10
Expect StCalc (42): StCalc(42)
Expect StCalc (5): StCalc (5)
ERROR (line 86 in file 'fullp0.cc') : (Stcalc ::push()) stack overflow*/

Last edited by serdengil; Sep 15th, 2009 at 11:38 am.

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VernonDozier VernonDozier is offline

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Re: SSales Tax Calculator Class

Sep 15th, 2009

Start by making sure you understand what exactly you are supposed to do. Start by making sure you understand what all of these functions are supposed to do and why he has main the way he has it. Start by spending a considerable amount of time doing all of these problems with pencil and paper till you know what everything represents. Then write some functions and test them with a simpler main to make sure it all works appropriately. When it does, go back to his main and try it.

Code tags are like this:

[code=C++]
// paste code here
[/code]

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Lerner

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Re: SSales Tax Calculator Class

Sep 15th, 2009

I've never seen sequential dot operators used like this:

myClass a;
a.enter().push();

but I like learning new things, so if someone can confirm line two above as valid syntax assuming enter() and push() are valid methods for a myClass object, I'll be wiser than I am now.

Klatu Barada Nikto

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serdengil

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Re: SSales Tax Calculator Class

Sep 15th, 2009

Thank you Vernon Dozier,

I just understand that,

There should be a class named StCalc and it also has enter, push, mul, div, sub, pop functions. The enter function help me to keep the new number and push is kind a storing this number . And all the other functions like math functions mul is multiplying new number and keepin number.

right?

Am I on the righ way...

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
//
int main(){
StCalc a;
a.enter(2); //screen has 2
a.push() .enter(3); //2 on stack screen has 3
a.push() .add() .pop(); // 2 3 on stack, add, pop to screen which has 5
cout<<"Expect StCalc (5): "<<a<<endl; // test "<<"
cout<<"Expect 5: "<<a.getScreen()<<endl; //test getScreen()
a.push() .enter(4); //5 on stack 4 on screen
cout<<"Expect StCalc (20): "<<a.push() .mul() .pop<<endl;
a.push() .enter(8); //stack has 20 screen has 8
cout<<"Expect StCalc(2.5): '<<a.push() .sub() .pop() <<endl;
a.push() .enter(3); //2.5 on stack, 3 on screen
cout<<"Expect StCalc(-0.5): <<a.push() .sub() .pop()<<endl;
a<<42; //test overload "<<", which stores 42 on screen
cout<< "expect 10: ""<<(a==42)<<(==3)<<endl; //test boolen ==
cout<<"Expect StCalc (42): "<<a<<endl;
a.enter(3);
a+=2; //test overloaded +=
cout<<"Expect StCalc(5): "<<a<<endl;
a.push() .enter(0);
//a.push() div(); //should crash
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
}
 
void check(bool b, char *mess, int line, char *filename) {
if(!b){
cerr<<"ERROR(line "<<line<<" in file '""<<filename<<"'): "<<mess<<endl;
exit(1);
}
}
 
/* the OUTPUT
 
Expect StCalc (5): StCalc (5)
Expect 5: 5
Expect StCalc (20) tCalc(20)
Expect StCalc (2.5): StCalc(2.5)
Expect StCalc (-0.5): StCalc (-0.5)
Expect 10: 10
Expect StCalc (42): StCalc(42)
Expect StCalc (5): StCalc (5)
ERROR (line 86 in file 'fullp0.cc') : (Stcalc ::push()) stack overflow*/
 
//
int main(){
StCalc a;
a.enter(2); //screen has 2
a.push() .enter(3); //2 on stack screen has 3
a.push() .add() .pop(); // 2 3 on stack, add, pop to screen which has 5
cout<<"Expect StCalc (5): "<<a<<endl; // test "<<"
cout<<"Expect 5: "<<a.getScreen()<<endl; //test getScreen()
a.push() .enter(4); //5 on stack 4 on screen
cout<<"Expect StCalc (20): "<<a.push() .mul() .pop<<endl;
a.push() .enter(8); //stack has 20 screen has 8
cout<<"Expect StCalc(2.5): '<<a.push() .sub() .pop() <<endl;
a.push() .enter(3); //2.5 on stack, 3 on screen
cout<<"Expect StCalc(-0.5): <<a.push() .sub() .pop()<<endl;
a<<42; //test overload "<<", which stores 42 on screen
cout<< "expect 10: ""<<(a==42)<<(==3)<<endl; //test boolen ==
cout<<"Expect StCalc (42): "<<a<<endl;
a.enter(3);
a+=2; //test overloaded +=
cout<<"Expect StCalc(5): "<<a<<endl;
a.push() .enter(0);
//a.push() div(); //should crash
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
}

void check(bool b, char *mess, int line, char *filename) {
if(!b){
cerr<<"ERROR(line "<<line<<" in file '""<<filename<<"'): "<<mess<<endl;
exit(1);
}
}

/* the OUTPUT

Expect StCalc (5): StCalc (5)
Expect 5: 5
Expect StCalc (20) tCalc(20)
Expect StCalc (2.5): StCalc(2.5)
Expect StCalc (-0.5): StCalc (-0.5)
Expect 10: 10
Expect StCalc (42): StCalc(42)
Expect StCalc (5): StCalc (5)
ERROR (line 86 in file 'fullp0.cc') : (Stcalc ::push()) stack overflow*/

Last edited by serdengil; Sep 15th, 2009 at 1:17 pm. Reason: Reply to Vernon Dozier

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Salem

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Void main'ers are DOOMed

Re: SSales Tax Calculator Class

Sep 15th, 2009

Look at all the pretty colours in your post.
Blue means it's a string - is it really meant to be a string?

Consider looking for the mis-placed "

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VernonDozier VernonDozier is offline

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Re: SSales Tax Calculator Class

Sep 15th, 2009

•

Originally Posted by Lerner

I've never seen sequential dot operators used like this:

myClass a;
a.enter().push();

but I like learning new things, so if someone can confirm line two above as valid syntax assuming enter() and push() are valid methods for a myClass object, I'll be wiser than I am now.

The syntax is fine, depending on what everything returns. If the methods return myClass objects, you're good to go. Here's a valid, though completely meaningless implementation.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
using namespace std;
 
class myClass
{
      public:       
             myClass ()
             {
             }
 
             myClass enter ()
             {
                 return *this;
             }
 
             myClass push ()
             {
                 return *this;
             }
 
      private:
              int someAttribute;
};
 
 
 
int main()
{    
  myClass a;
  a.enter ().push ();
  cin.get ();
  return 0;     
}
#include <iostream>
using namespace std;

class myClass
{
      public:       
             myClass ()
             {
             }
             
             myClass enter ()
             {
                 return *this;
             }
             
             myClass push ()
             {
                 return *this;
             }
             
      private:
              int someAttribute;
};


     
int main()
{    
  myClass a;
  a.enter ().push ();
  cin.get ();
  return 0;     
}

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serdengil

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Re: SSales Tax Calculator Class

Sep 15th, 2009

I corrected the missing "

Thank you...

But still cant get an answer

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
//
int main(){
StCalc a;
a.enter(2); //screen has 2
a.push() .enter(3); //2 on stack screen has 3
a.push() .add() .pop(); // 2 3 on stack, add, pop to screen which has 5
cout<<"Expect StCalc (5): "<<a<<endl; // test "<<"
cout<<"Expect 5: "<<a.getScreen()<<endl; //test getScreen()
a.push() .enter(4); //5 on stack 4 on screen
cout<<"Expect StCalc (20): "<<a.push() .mul() .pop<<endl;
a.push() .enter(8); //stack has 20 screen has 8
cout<<"Expect StCalc(2.5): "<<a.push() .sub() .pop() <<endl;
a.push() .enter(3); //2.5 on stack, 3 on screen
cout<<"Expect StCalc(-0.5): "<<a.push() .sub() .pop()<<endl;
a<<42; //test overload "<<", which stores 42 on screen
cout<< "expect 10: "<<(a==42)<<(==3)<<endl; //test boolen ==
cout<<"Expect StCalc (42): "<<a<<endl;
a.enter(3);
a+=2; //test overloaded +=
cout<<"Expect StCalc(5): "<<a<<endl;
a.push() .enter(0);
//a.push() div(); //should crash
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
}
 
void check(bool b, char *mess, int line, char *filename) {
if(!b){
cerr<<"ERROR(line "<<line<<" in file '"<<filename<<"'): "<<mess<<endl;
exit(1);
}
}
 
/* the OUTPUT
 
Expect StCalc (5): StCalc (5)
Expect 5: 5
Expect StCalc (20) tCalc(20)
Expect StCalc (2.5): StCalc(2.5)
Expect StCalc (-0.5): StCalc (-0.5)
Expect 10: 10
Expect StCalc (42): StCalc(42)
Expect StCalc (5): StCalc (5)
ERROR (line 86 in file 'fullp0.cc') : (Stcalc ::push()) stack overflow*/
//
int main(){
StCalc a;
a.enter(2); //screen has 2
a.push() .enter(3); //2 on stack screen has 3
a.push() .add() .pop(); // 2 3 on stack, add, pop to screen which has 5
cout<<"Expect StCalc (5): "<<a<<endl; // test "<<"
cout<<"Expect 5: "<<a.getScreen()<<endl; //test getScreen()
a.push() .enter(4); //5 on stack 4 on screen
cout<<"Expect StCalc (20): "<<a.push() .mul() .pop<<endl;
a.push() .enter(8); //stack has 20 screen has 8
cout<<"Expect StCalc(2.5): "<<a.push() .sub() .pop() <<endl;
a.push() .enter(3); //2.5 on stack, 3 on screen
cout<<"Expect StCalc(-0.5): "<<a.push() .sub() .pop()<<endl;
a<<42; //test overload "<<", which stores 42 on screen
cout<< "expect 10: "<<(a==42)<<(==3)<<endl; //test boolen ==
cout<<"Expect StCalc (42): "<<a<<endl;
a.enter(3);
a+=2; //test overloaded +=
cout<<"Expect StCalc(5): "<<a<<endl;
a.push() .enter(0);
//a.push() div(); //should crash
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
a.push() .push() .push() .push() .push() .push() .push();
}

void check(bool b, char *mess, int line, char *filename) {
if(!b){
cerr<<"ERROR(line "<<line<<" in file '"<<filename<<"'): "<<mess<<endl;
exit(1);
}
}

/* the OUTPUT

Expect StCalc (5): StCalc (5)
Expect 5: 5
Expect StCalc (20) tCalc(20)
Expect StCalc (2.5): StCalc(2.5)
Expect StCalc (-0.5): StCalc (-0.5)
Expect 10: 10
Expect StCalc (42): StCalc(42)
Expect StCalc (5): StCalc (5)
ERROR (line 86 in file 'fullp0.cc') : (Stcalc ::push()) stack overflow*/

[/QUOTE]

Last edited by serdengil; Sep 15th, 2009 at 1:33 pm.

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Lerner

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Re: SSales Tax Calculator Class

Sep 15th, 2009

VernonDozier, thanks. I knew that explained why the << and the + operator can be used sequentially, but I've never seen the dot operator used that way. I have used the dot operator sequentially to get infromation or do things for encapsulated class/struct members, but have never seen this use of it before.

serdengil, post the code you have written for the StCalc class, not the driver program. It looks to me like you will need several variable members in the class in addition to the methods necessary to be able to run the code. It looks like you will need at least one variable to store input, one variable to store an answer and one stack variable. Only you know if you can use code for a prewritten stack or whether you will need to write your own.

Start out by commenting all of the program in main() except the declaration of the StCalc variable and a line to display either or both of the member variables. Once you can do that then write code to do each method you need to create for the program one at a time. If you have to write code to be sure the method is working correctly before it's actually used in the program as written, good for you, just be sure you remove it after the function has been thouroughly tested.

Klatu Barada Nikto

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Join Date: Sep 2009

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serdengil

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Newbie Poster

Re: SSales Tax Calculator Class

Sep 15th, 2009

•

Originally Posted by Lerner

VernonDozier, thanks. I knew that explained why the << and the + operator can be used sequentially, but I've never seen the dot operator used that way. I have used the dot operator sequentially to get infromation or do things for encapsulated class/struct members, but have never seen this use of it before.

serdengil, post the code you have written for the StCalc class, not the driver program. It looks to me like you will need several variable members in the class in addition to the methods necessary to be able to run the code. It looks like you will need at least one variable to store input, one variable to store an answer and one stack variable. Only you know if you can use code for a prewritten stack or whether you will need to write your own.

Start out by commenting all of the program in main() except the declaration of the StCalc variable and a line to display either or both of the member variables. Once you can do that then write code to do each method you need to create for the program one at a time. If you have to write code to be sure the method is working correctly before it's actually used in the program as written, good for you, just be sure you remove it after the function has been thouroughly tested.

I just wrote:

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