Re: [Dev-C++] & and *

[Daniel G. <sp...@ho...>]

Umm, am I missing something here?

// Forward declaration of getData
void getData(int& lengCo,int& lengGro,string& comet,string& group);
The & in this function prototype means the function accepts a reference 
(changes affect the actual variable, not a copy) for those variables. So

void ChangeSpeed(int& Speed)
{
    Speed = 7;
}

// In main()
int Speed = 0;

// Call ChangeSpeed
ChangeSpeed(Speed);

// Speed is now 7


If I had done


void ChangeSpeed(int Speed)
{
    Speed = 7;
}

// In main()
int Speed = 0;

// Call ChangeSpeed
ChangeSpeed(Speed);

// Speed is still 0 because we only changed a copy


The * means a pointer. So


void ChangeSpeed(int* Speed)
{
    // 'dereference' the pointer - act on what it is pointing to
    *Speed = 7;
}

// In main()
int MySpeed = 0;

// Pointer points to MySpeed - in this case & means the address of
int* Speed = &MySpeed;

// Call ChangeSpeed
ChangeSpeed(Speed);

// MySpeed is now 7


Apologies if I have got the wrong end of the stick,

Daniel


>From: Jeeun Cho <koo...@ya...>
>To: dev c <dev...@li...>
>Subject: [Dev-C++] & and *
>Date: Tue, 25 Feb 2003 23:03:16 -0800 (PST)
>
>void
>getData(int&lengCo,int&lengGro,string&comet,string&group);
>void Convert(int lengCo,int lengGro,string
>comet,string
>group,vector<int>&ComNum,vector<int>&GroNum);
>void
>modNum(int&modCom,int&modGro,vector<int>ComNum,vector<int>GroNum,int
>lengCo,int lengGro);
>
>this is part of my program...and..as u can see, i used
>& between a data type and a changeable variable..(i
>was taught lyke that in my c++ class at school)..
>but i found out that people are using * instead of &
>for changeable variables...
>so..i chaged every & to * and compiled it, but i got
>lotta errors; when i used & and compiled, i didnt get
>any error..
>
>what should i use or do?
>
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