User-Defined Function - part 2

[Duki]

Hey everyone, this is a big one.

The question has asked that I define functions and then write the function main to test the functions I wrote. I keep getting the following error at my first cout in main:

error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'void' (or there is no acceptable conversion)

I'm not sure what this is saying.
In addition, I need help with defining two of my functions and writing code to test them. They are as follows:

1. Write the definition of the function nextChar that sets the value of z to the next character stored in z.

2. Write the definition of the function funcOne that prompts the user to input a number. The function then changes the value of x to 2 times the old value of x plus the value of y minus the value entered by the user.

Now, with #2 I'm pretty sure I have the function defined right, though I don't know how to test it. #1 though, I have no clue how to define that function, though I did attempt it =/.

Could someone look through my code, and let me know if they notice any huge mistakes? This is our second chapter on user-defined functions, so I'm still learning about call by reference and whatnot. I have commented my code minimaly to assist you in finding the parts I'm having a tough time with.

Thanks guys! :mrgreen:

code:

#include <iostream>
#include <iomanip>
using namespace std ;

void initialize ( int& , int& , char& ) ;
void getHoursRate ( double& , double& ) ;
double payCheck ( double& , double& ) ;
void printCheck ( double , double, double ) ;
int main()
{
    int x ;
    int y ;
    int w ;

    char z ;

    double rate ;
    double hours ;
    double amount ;

    cout << initialize( x , y , z ) << endl ;            //error is here
    cout << getHoursRate() << endl ;
    cout << payCheck( hours , rate ) << endl ;
    printCheck( hours, rate, amount ) << endl ;
    cout << funcOne( w, x, y ) ;    //confusion starts here
    cout <<    
}

void initialize ( int& x, int& y, char& z )
{
    x = y = 0 ;
    z = ' ' ;
}

void getHoursRate ( double& hours , double& rate )
{
    cout << "Hours worked:  " << endl ;
    cin >> hours ;
    cout << "Rate:  " << endl ;
    cin >> rate ;
}

double payCheck ( double& hours, double& rate )
{
    double pay ;

    int ot ;

    if ( (hours - 40 <= 0 ) )
        pay = rate * hours ;
    else
    {
        ot = hours - 40 ;
        pay = (40 * rate) + (ot * rate * 1.5) ;
    }
    return pay ;
}

void printCheck ( double hours , double rate , double pay )
{
    cout << setprecision(2) << fixed << showpoint << setfill('.') << left ;
    cout << "Hours" << setw(15) << "Rate" << setw(15) << "Amount Due" << endl << endl ;
    cout << hours << setw(15) << "$" << rate << setw(15) << "$" << pay << endl ;
}

void funcOne ( double in, int x, int y )        //number 2 in my post
{
    cout << "Input a value:  " << endl ;
    cin >> in ;

    x = x * x + ( y - in ) ;
}

char nextChar ( char ch )                    //number 1 in my post
{
    ch = ch++ ;
}

[John A]

Don't have time to check over the rest of the code, but I can tell you what is wrong here:

cout << initialize( x , y , z ) << endl ;            //error is here

initialize returns nothing, so cout has nothing to print. If you want to initalize the variables, try calling the function in a separate line instead of mixing it in with the cout call.

[ft3ssgeek]

2) Write the definition of the function funcOne that prompts the user to input a number. The function then changes the value of x to 2 times the old value of x plus the value of y minus the value entered by the user.

Now, with #2 I'm pretty sure I have the function defined right, though I don't know how to test it.

code:

void funcOne ( double in, int x, int y )        //number 2 in my post
{
    cout << "Input a value:  " << endl ;
    cin >> in ;

    x = x * x + ( y - in ) ;                //  <----Wrong
}

end quote.

With this function you are squaring x instead of doubling it (ie use 2*x instead of x*x). To test it, simply do some simple math in your head, using different values of x and y....then implement that in your code...if your code gives you different answers, then, unless you did the math wrong yourself, you know there is a problem with your code...

[ft3ssgeek]

As for part 1, I believe the instructions are referring to c-strings...how much do you know about c-strings?

[Duki]

Ok, I've modified my code, and am getting an error that says:

[I]error C2563: mismatch in formal parameter list[/I]

This is at the same line with the comment [B]//error is here[/B]

I've called the void functions outside of a cout, and have put cout statements inside of the function to test them. What am I doing wrong? =/

#include <iostream>
#include <iomanip>
using namespace std ;
void initialize ( int& , int& , char& ) ;
void getHoursRate ( double& , double& ) ;
double payCheck ( double& , double& ) ;
void printCheck ( double , double, double ) ;
void funcOne ( doulbe, int, int ) ;
void nextChar ( char ) ;
int main()
{
    int x ;
    int y ;
    int w ;

    char z ;
    double rate ;
    double hours ;
    double amount ;
    initialize( x , y , z ) << endl ;            //error is here
    getHoursRate() << endl ;
    cout << payCheck( hours , rate ) << endl ;
    printCheck( hours, rate, amount ) << endl ;
    funcOne( w, x, y ) ;    //confusion starts here
 nextChar ( z ) ;
}
void initialize ( int& x, int& y, char& z )
{
    x = y = 0 ;
    z = ' ' ;
    cout << "Inside initialize-function:  " << endl ;
    cout << "The values of 'x', 'y' and 'z', respectively are:  " x << "\t" << y << "\t" << z << endl << endl ;
}
void getHoursRate ( double& hours , double& rate )
{
    cout << "Hours worked:  " << endl ;
    cin >> hours ;
    cout << "Rate:  " << endl ;
    cin >> rate ;
    cout << "Inside getHoursRate-function:  " << endl ;
    cout << "The values of 'hours' and 'rate', respectively are:  " << hours << "\t" << rate << endl << endl ;
}
double payCheck ( double& hours, double& rate )
{
    double pay ;

    int ot ;
    if ( (hours - 40 <= 0 ) )
        pay = rate * hours ;
    else
    {
        ot = hours - 40 ;
        pay = (40 * rate) + (ot * rate * 1.5) ;
    }
    return pay ;
}
void printCheck ( double hours , double rate , double pay )
{
    cout << setprecision(2) << fixed << showpoint << setfill('.') << left ;
    cout << "Hours" << setw(15) << "Rate" << setw(15) << "Amount Due" << endl << endl ;
    cout << hours << setw(15) << "$" << rate << setw(15) << "$" << pay << endl ;
}
void funcOne ( double in, int x, int y )        //number 2 in my post
{
    cout << "Input a value:  " << endl ;
    cin >> in ;
    x = x * 2 + ( y - in ) ;
    cout << "Inside funcOne-function:  " << endl ;
    cout << "The value of 'x' is:  " << x << endl << endl ;
}
char nextChar ( char ch )                    //number 1 in my post
{
    cout << "Inside nextChar-function:  " << endl ;
    cout << "Initial character stored in 'ch' is:  " << ch << endl ;
    ch = ch++ ;
    cout << "The character stored in 'ch' after incriment is:  " << ch << endl << endl ;
}

[~s.o.s~]

initialize( x , y , z ) << endl ; You can't do this in C++ esp when initialize doesn't return anything and even if it did, you aren't specifying the stream to which the output should be redirected.

[Duki]

As for part 1, I believe the instructions are referring to c-strings...how much do you know about c-strings?

i don't =/

[WaltP]

As for part 1, I believe the instructions are referring to c-strings...how much do you know about c-strings?

I don't think so. Although, I don't know what the instructions mean, either.

Can you give us an example of the operation?

[Duki]

Just an update, thanks to everyone who helped. Here's the finalized code. This one is solved :D

/*****************************************************
* COSC 230 - Structured Programming
* Chapter 7:  Programming Exercise 1
* Apr. 4, 2007
*
* Discription:
*    blah
******************************************************/

//header files
#include <iostream>
#include <iomanip>
using namespace std ;

//function prototypes
void initialize ( int& , int& , char& ) ;
void getHoursRate ( double& , double& ) ;
double payCheck ( double& , double& ) ;
void printCheck ( double , double, double ) ;
void funcOne ( double, int, int ) ;
void nextChar ( char ) ;

int main()
{
    int x ;
    int y ;
    int w ;

    char z ;

    double rate ;
    double hours ;
    double amount ;

    initialize( x , y , z ) ;    //test initialize-func.
    getHoursRate(hours, rate) ;    //test initialize-func.
    amount = payCheck( hours, rate ) ;        //initialize amount to paycheck-func.
    cout << "*** Inside payCheck-function ***" << endl << payCheck( hours , rate ) << endl ;    //test payCheck-func.
    printCheck( hours, rate, amount ) ;    //test printCheck-func.
    funcOne( w, x, y ) ;    //test funcOne-func.
    nextChar ( z ) ;    //test nextChar-func.
}

void initialize ( int& x, int& y, char& z )
{
    x = y = 0 ;
    z = ' ' ;

    cout << "*** Inside initialize-function ***" << endl ;
    cout << "The values of 'x' and 'y', respectively are:  " << x << " and " << y << endl ;
    cout << "The character stored in z is:  " << z << "(space character)" << endl << endl ;
}//end void initialize

void getHoursRate ( double& hours , double& rate )
{
    cout << "Hours worked:  " << flush ;
    cin >> hours ;
    cout << "Rate:  " << flush ;
    cin >> rate ;

    cout << endl << "*** Inside getHoursRate-function ***" << endl << endl ;
    cout << "The values of 'hours' and 'rate', respectively are:  " << hours << "\t" << rate << endl << endl ;
}//end getHoursRate

double payCheck ( double& hours, double& rate )
{
    double pay ;

    int ot ;

    if ( (hours - 40 <= 0 ) )
        pay = rate * hours ;
    else
    {
        ot = hours - 40 ;
        pay = (40 * rate) + (ot * rate * 1.5) ;
    }
    return pay ;
}//end double payCheck

void printCheck ( double hours , double rate , double amount )
{
    cout << "*** Inside printCheck-function ***" << endl ;
    cout << setprecision(2) << fixed << showpoint << setfill('.') ;
    cout << "Hours" << setw(20) << right << "Rate" << setw(25) << right << "Amount Due" << endl ;
    cout << hours << setw(15) << "$" << rate << setw(15) << "$" << amount << endl << endl ;
}//end void printCheck

void funcOne ( double in, int x, int y )
{
    cout << "Input a value:  " << flush ;
    cin >> in ;
    cout << endl ;

    x = x * 2 + ( y - in ) ;

    cout << "*** Inside funcOne-function ***" << endl ;
    cout << "The value of 'x' is:  " << x << endl << endl ;
}//end void funcOne

void nextChar ( char ch )
{
    cout << "*** Inside nextChar-function ***" << endl ;
    cout << "Initial character stored in 'ch' is:  " << ch << endl ;

    ch = ch++ ;

    cout << "The character stored in 'ch' after increment is:  " << ch << endl << endl ;
}//end nextChar