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compile error

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Join Date: Apr 2006

Posts: 15

Reputation: puppy is an unknown quantity at this point

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puppy

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Newbie Poster

compile error

May 9th, 2006

Hi,
Can someone tell me how to fix the function below. I am getting this compile error regarding the last line:
cannot convert `const double' to `const double*' in return
What should I return according to the function parameters I've written?

Thanks.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
const double * maximum(const double a[], int size)
{
    if (size == 0) return NULL;
    const double *highest = a;
    for (int i = 0; i < size; i++)
        if (a[i] > *highest)
        {
            *highest == a[i];
        }
    return *highest;
const double * maximum(const double a[], int size)
{
    if (size == 0) return NULL;
    const double *highest = a;
    for (int i = 0; i < size; i++)
        if (a[i] > *highest)
        {
            *highest == a[i];
        }
    return *highest;

Last edited by Dave Sinkula; May 9th, 2006 at 10:11 pm.

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Join Date: Jul 2005

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Lerner

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Re: compile error

May 9th, 2006

The syntax error being reported means you have to return highest, not the highest derefenced.

The logic error is that you need to have the ability to change the value of highest so don't try to force highest to be a const double in the first place.

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Join Date: Mar 2006

Posts: 176

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dubeyprateek dubeyprateek is offline

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Junior Poster

Re: compile error

May 12th, 2006

hi
There are two things first

Help with Code Tags

C Syntax (Toggle Plain Text)

 const double *highest = a;

this line says highest is a pointer to a costant means u cant change the content highest is pointing to, next

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
if (a[i] > *highest)
        {
            *highest == a[i]; // "==" ??
        }
if (a[i] > *highest)
        {
            *highest == a[i]; // "==" ??
        }

removing that if u do it like

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
if (a[i] > *highest)
        {
            *highest = a[i];
        }
if (a[i] > *highest)
        {
            *highest = a[i];
        }

u will be trying to change a contant, which is illegal.

better if u write

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
const double * maximum(const double a[], int size)
{
    if (size == 0) return NULL;
    double *highest = (double*)a;
    for (int i = 0; i < size; i++)
        if (a[i] > *highest)
        {
            *highest = a[i];
        }
    return highest;
}
const double * maximum(const double a[], int size)
{
    if (size == 0) return NULL;
    double *highest = (double*)a;
    for (int i = 0; i < size; i++)
        if (a[i] > *highest)
        {
            *highest = a[i];
        }
    return highest;
}