dev-cpp-users

Re: [Dev-C++] Newbie Needs Help

[metalseb <met...@fr...>]

>   // ThirdNumber Function
>   int ThirdNumber(int NumberThree)
>   {
>     NumberThree = int NumberOne - int NumberTwo;
>     cout << "You have spent $" << NumberThree << " dollars today " << endl;
>   }

The compiler doesn't know what to do with this code gathering two declarations of int vars 
minusing themselves at the same time. Remove that line.

Remember that NumberOne and NumberTwo are not global vars so they are not known inside 
the ThirdNumber function. Only in the main section, where they are declared. By the way, 
remove the int return values of each function since they don't do anything but asking for a user 
input.

All you have to do in the main section is :

ThirdNumber(NumberTwo-NumberOne);

And in the ThirdNumber func :

void  ThirdNumber(int NumberThree)
{
     cout << "You have spent $" << NumberThree << " dollars today " << endl;
 }

Kind regards

--
Seb

RE: [Dev-C++] Newbie Needs Help

[Santiago P. C. <San...@yd...>]

Hi John,

Please take a closer look to:
- function calling mechanism and return Values,
- variables scopes,
- passing variables by reference or by value,

In your code you are...

1st) ...Passing variables by value _NOT_BY_REFERENCE_ so you cannot modif=
y
its value inside the function you are passing the variable to.

=09int FirstNumber(int NumberOne)
=09{
=09	cout << "Enter how much money you had this morning $";
=09	cin >> NumberOne;		// <=3D this NumberOne is NOT
the same as main's NumberOne
=09}

2nd) ..."Mixing" the way a variable is defined and the way that variable'=
s
content is handled.

=09int ThirdNumber(int NumberThree)
=09{
=09  // NumberThree =3D int NumberOne - int NumberTwo;	// <=3D WRONG
STATEMENT
=09  //		you are "trying to define" 'NumberOne' and
'NumberTwo' erroneously and in a local scope,
=09  // 		please have in mind that you are not referencing
main's 'NumberOne' and 'NumberTwo'

=09  cout << "You have spent $" << NumberThree << " dollars today " <<
endl;
=09}

3rd) ...defining functions to return an int value but not returning it:

=09int FirstNumber(int NumberOne)
=09{
=09	cout << "Enter how much money you had this morning $";
=09	cin >> NumberOne;		// <=3D this NumberOne is NOT
the same as main's NumberOne

=09	// There must be a return statement here!!!!
=09}

4th) ..."thinking" that you are calling functions while you're NOT doing
that...

// Main Function
int main(int argc, char *argv[])
{
=20   int NumberOne;
=20   int NumberTwo;
=20   int NumberThree;

=09//  Here you are "trying to REdefine" the functions, NOT calling
them
=20   int FirstNumber(int NumberOne);	=09
=20   int SecondNumber(int NumberTwo);
=20   int ThirdNumber(int NumberThree);

=20   system("PAUSE");
=20   return 0;
}

There are also some "design issues" that I think you should take a look a=
t;
so I've modified your code the way I think it should look like (I've
modified some names in order to clarify the code ;oD):

#include <iostream>
#include <string>

/*
This program in designed to take input from the user,
in the form of a number and compute the output.
The program is then to display the output back to the user.
*/

// Function Definitions
int GetFirstNumber();  =20
int GetSecondNumber(); =20
void ShowThirdNumber(int iNumberOne, int iNumberTwo);

// GetFirstNumber Function
// The function gets an input from the user and returns it
int GetFirstNumber()
{
=20 int iLocalNumberOne =3D 0;
=20 cout << "Enter how much money you had this morning:" << endl ;
=20 cin >> iLocalNumberOne;

=20 return iLocalNumberOne;
}

// GetSecondNumber Function
// The function gets an input from the user and returns it
int GetSecondNumber()
{
=20 int iLocalNumberTwo =3D 0;
=20 cout << "Enter how much money you have now:" << endl;
=20 cin >> iLocalNumberTwo;

=20return iLocalNumberTwo;
}

// ShowThirdNumber Function
void ShowThirdNumber(int iNumberOne, int iNumberTwo)
{
=20 int iLocalNumberThree =3D iNumberOne - iNumberTwo;
=20 cout << "You have spent " << iLocalNumberThree << " dollars today " <=
<
endl;
}

// Main Function
int main(int argc, char *argv[])
{
=09// Retrieve first Number by calling the appropriate function and
=09// store it at int variable called 'iTheFirstNumber'
=09int iTheFirstNumber =3D GetFirstNumber();

=09// Retrieve second Number by calling the appropriate function and
=09// store it at int variable called 'iTheSecondNumber'
=09int iTheSecondNumber =3D GetSecondNumber();

=09// Call the apropriate function with the previously acquired values
=09// in order to print the result to the screen
=09ShowThirdNumber(iTheFirstNumber, iTheSecondNumber);

=20   system("PAUSE");
=20   return 0;
}

Hope this helps!!!

Regards, Santy

-----Original Message-----
From: John Ellison [mailto:j_...@ip...]=20
Sent: mi=E9rcoles, 18 de septiembre de 2002 12:00
To: dev...@li...
Subject: [Dev-C++] Newbie Needs Help


Gudday All,

=20   I have a small problem which I cant seem to find the answer to. I w=
as
hoping that someone could help. I am just beginning to learn c++, so the
code is not to complex. My problem lies in the compilation process. I am
unsure as to how to fix the compilation error.

Thanks to everybody.
Have a good one.
John

Here is the compilation error.

32 six.cpp parse error before `-'

And here is my source code :-

#include <stdio.h>
#include <iostream>
#include <string>

/*
This program in designed to take input from the user,
in the form of a number and compute the output.
The program is then to display the output back to the user.
*/

int FirstNumber(int NumberOne);   // Function Definitions
int SecondNumber(int NumberTwo);  // Function Definitions
int ThirdNumber(int NumberThree); // Function Definitions

// FirstNumber Function
int FirstNumber(int NumberOne)
{
=20 cout << "Enter how much money you had this morning $";
=20 cin >> NumberOne;
}

// SecondNumber Function
int SecondNumber(int NumberTwo)
{
=20 cout << "Enter how much money you have now $";
=20 cin >> NumberTwo;
}

// ThirdNumber Function
int ThirdNumber(int NumberThree)
{
=20 NumberThree =3D int NumberOne - int NumberTwo;
=20 cout << "You have spent $" << NumberThree << " dollars today " << end=
l;
}

// Main Function
int main(int argc, char *argv[])
{
=20   int NumberOne;
=20   int NumberTwo;
=20   int NumberThree;

=20   int FirstNumber(int NumberOne);
=20   int SecondNumber(int NumberTwo);
=20   int ThirdNumber(int NumberThree);

=20   system("PAUSE");
=20   return 0;
}


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