QSort

**skumar7777** · 2nd December 2008, 02:42

Hi,

I have a problem with qSort, illustrated as follows:

Qt Code:

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#include <qhash.h>
 
struct TDATA {
	QString		emp_name;
	float		salary;
};
 
QHash	< uint, TDATA> emps;
 
bool salaryLessThan(const TDATA &e1, const TDATA &e2) {
	return (e1.salary < e2.salary);
}
 
int main(int argc, char *argv[])
{
 
    qStableSort(emps.begin(), emps.end(), salaryLessThan);
    return 1;
}

#include <qhash.h>

struct TDATA {
	QString		emp_name;
	float		salary;
};

QHash	< uint, TDATA> emps;

bool salaryLessThan(const TDATA &e1, const TDATA &e2) {
	return (e1.salary < e2.salary);
}

int main(int argc, char *argv[])
{

    qStableSort(emps.begin(), emps.end(), salaryLessThan);
    return 1;
}

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Basically, I want to sort based on the values in the Hash.

Compiling this gives a long error message as attached:

Can anyone please help me out?

Thanks.

**pgorszkowski** · 2nd December 2008, 05:13

You cannot use qStableSort to sort qHash because qHash does not have Random Access Iterators. If you want sorting by qStableSort you have to use qVector or qList.

http://doc.trolltech.com/4.3/qtalgor...ml#qStableSort

http://doc.trolltech.com/4.3/qtalgor...cess-iterators

**skumar7777** · 2nd December 2008, 05:23

Hi,

Thanks for responding.

Please take a look at http://doc.trolltech.com/4.4/qtalgorithms.html.

It clearly states

You can use these algorithms with any container class that provides STL-style iterators, including Qt's QList, QLinkedList, QVector, QMap, and QHash classes.

I think it is a problem with my function definition. I have looked at similiar threads but could not figure out what was required since my function is global.

Thanks again.