DaniWeb Forum Index > Software Development > C++

C++ RSS

User-Defined Function - setup right?

Please support our C++ advertiser: Intel Parallel Studio Home

Thread Solved

•

Join Date: Jun 2006

Posts: 1,169

Reputation: Duki has a spectacular aura about

Solved Threads: 9

Duki

Offline

Veteran Poster

User-Defined Function - setup right?

Apr 3rd, 2007

Hey all,

I'm doing hw, and I did a desk-check for this program and got completely different answers than that of the computer when the program was put into the compiler.

The question says to consider the function defaultParam

 Help with Code Tags 
(Toggle Plain Text)
 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
void defaultParam ( int u , int v = 5 , double z = 3.2 )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}
void defaultParam ( int u , int v = 5 , double z = 3.2 )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}
     Help with Code Tags   c++ Syntax (Toggle Plain Text)    void defaultParam ( int u , int v = 5 , double z = 3.2 ){    int a ;    u = u + static_cast<int>( 2 * v + z ) ;    a = u + v * z ;    cout << "a = " << a << endl ;} void defaultParam ( int u , int v = 5 , double z = 3.2 )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}  

What is the output of the following function calls?

defaultParam(6) ;
defaultParam(3, 4) ;
defaultParam(3, 0, 2.8) ;

Here is my code:

 Help with Code Tags 
(Toggle Plain Text)
 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
#include <iostream>
using namespace std ;
 
void defaultParam ( int u , int v = 5 , double z = 3.2 ) ;
int main ()
{
    defaultParam(6) ;
    defaultParam(3 , 4) ;
    defaultParam(3 , 0 , 2.8) ;
 
    return 0 ;
}
 
void defaultParam ( int u , int v , double z )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}
#include <iostream>
using namespace std ;

void defaultParam ( int u , int v = 5 , double z = 3.2 ) ;
int main ()
{
    defaultParam(6) ;
    defaultParam(3 , 4) ;
    defaultParam(3 , 0 , 2.8) ;

    return 0 ;
}

void defaultParam ( int u , int v , double z )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}
     Help with Code Tags   c++ Syntax (Toggle Plain Text)    #include <iostream>using namespace std ; void defaultParam ( int u , int v = 5 , double z = 3.2 ) ;int main (){    defaultParam(6) ;    defaultParam(3 , 4) ;    defaultParam(3 , 0 , 2.8) ;     return 0 ;} void defaultParam ( int u , int v , double z ){    int a ;    u = u + static_cast<int>( 2 * v + z ) ;    a = u + v * z ;    cout << "a = " << a << endl ;} #include <iostream>
using namespace std ;

void defaultParam ( int u , int v = 5 , double z = 3.2 ) ;
int main ()
{
    defaultParam(6) ;
    defaultParam(3 , 4) ;
    defaultParam(3 , 0 , 2.8) ;

    return 0 ;
}

void defaultParam ( int u , int v , double z )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}  

My output from this code is:

a = 35
a = 26
a = 5
Press any key to continue . . .

but when I did the desk-checking I got:

50
54.2
3

Is my program setup to give me the correct results? Or am I right? Or neither :mrgreen:?

It is practically impossible to teach good programming style to students that have had prior exposure to Basic; as potential programmers they are mentally mutilated beyond hope of regeneration.

-Edsger Dijkstra

•

Join Date: May 2006

Posts: 3,114

Reputation: WaltP has much to be proud of

Solved Threads: 281

WaltP

Offline

Posting Sensei

Re: User-Defined Function - setup right?

Apr 3rd, 2007

Your desk-check of the first call (6) is wrong.

The 3 Laws of the Procrastination Society:
1) Never do today that which can be put off until tomorrow
2) Tomorrow never comes

•

Join Date: Jun 2006

Posts: 1,169

Reputation: Duki has a spectacular aura about

Solved Threads: 9

Duki

Offline

Veteran Poster

Re: User-Defined Function - setup right?

Apr 3rd, 2007

hmm. is it 52?

•

Join Date: May 2006

Posts: 3,114

Reputation: WaltP has much to be proud of

Solved Threads: 281

WaltP

Offline

Posting Sensei

Re: User-Defined Function - setup right?

Apr 4th, 2007

Of course not....

•

Help with Code Tags

c++ Syntax (Toggle Plain Text)
void defaultParam ( int u , int v = 5 , double z = 3.2 )
{
    int a ;
    u = u + static_cast<int>( 2 * v + z ) ;
    a = u + v * z ;
    cout << "a = " << a << endl ;
}
void defaultParam ( int u , int v = 5 , double z = 3.2 ) { int a ; u = u + static_cast<int>( 2 * v + z ) ; a = u + v * z ; cout << "a = " << a << endl ; }
defaultParam(6) ;

What's u, v, and z?

Now what's u + (( 2 * v ) + z )? Replace u with this value -- as an integer

Now what's u + (v * z), also as an integer after calculating.

Are the lack of parentheses in the original equations throwing you? If so, prime reasong to paranthesize everything!

The 3 Laws of the Procrastination Society:
1) Never do today that which can be put off until tomorrow
2) Tomorrow never comes