Why qBinaryFind is giving compilation errors for std::list?

kranti.reddy2001

Please go through the following examples?
for example following program does not compile.
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
std::list<int> sl;
int num ;
for ( int i = 0 ; i < 20 ; i ++ )
{
sl.push_back ( i ) ;
}
std::cout <<"Enter the integer :: " ;
std::cin >> num ;
std::list<int>::const_iterator slItr = qBinaryFind ( sl , num );
if ( slItr != sl.end () )
std::cout <<"Num " << *slItr << " found " << std::endl;
else
std::cout <<"Num " << num << " not found " << std::endl;
return a.exec();
}

http://www.boostprogramming.com/forum/index.php/topic,748.0.html

Zlatomir

std::list does not have random access, it's a linked list not a vector, and qBinarySearch needs a container that has random access to the elements.

So you can use qBinaryFind with a std::vector, but you will need the overload that takes two iterators to specify a range (not the overload that takes a container, because of the stl that has a cbegin() and cend() to return const iterators):

@
std::vector<int> sl; int num ;
for ( int i = 0 ; i < 20 ; i ++ )
{ sl.push_back ( i ) ; }

std::cout <<"Enter the integer ::";
std::cin >> num ;

std::vector<int>::const_iterator slItr = qBinaryFind( sl.cbegin(), sl.cend() , num );

if ( slItr != sl.end () )
    std::cout <<"Num " << *slItr << " found" << std::endl;
else
    std::cout <<"Num "<< num << " not found" << std::endl;

@