#include <iostream>int main(){    int x;    std::cin >> std::showbase >> x;        std::cout << "You entered: " << x;}

Quote: http://www.cplusplus.com/reference/iostream/istream/operator>>/
The manipulators which have an effect when used on standard istream objects are:

boolalpha	 Alphanumerical bool values (manipulator function)noboolalpha	 No alphanumerical bool values (manipulator function)skipws		 Skip whitespaces (manipulator function)noskipws	 Do not skip whitespaces (manipulator function)dec		 Use decimal base (manipulator function)hex		 Use hexadecimal base (manipulator function)oct		 Use octal base (manipulator function)ws		 Extract whitespaces (manipulator function)

Other manipulators may be applicable to standard istream objects, but have no effect.

Quote:
Author: *********
Posted date: Friday, July 10, 2009 9:32:01 AM EDT
Last modified date: Friday, July 10, 2009 9:32:01 AM EDT
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cin >> showbase >> integer;// read input

cout << endl <<"The integer value in decimal format is " << dec << showbase << integer << endl;

this is what i did for each instance and it allows hexadecimal input and produces the correct results

Quote:
You beat me to the post. Yes, that is correct. However, the issue is how oct and dec basefield formats accept (input) and display (output) their respective base types correctly, but the hex basefield flag does not. (Though, assigning a hex value to a variable, rather than input, then displaying works as expected: i = 0x14; then, output i.)

When using the Borland compiler, and I'm assuming g++, the following code does not accept the leading 0x when entering a hexadecimal value--but dec, and oct do work as expected:

cout << "\nEnter hexadecimal value (e.g., 0x14): ";
//use showbase, rather than hex for hex values, problems with cin and leading 0x;
//that is (in Borland and g++), works with 14, but not 0x14
cin >> hex >> i;

The solution as you stated, is to use showbase, rather than the hex basefield flag:
cin >> showbase >> i;

Though, as mentioned, while VS.NET's compiler accepts the values as entered, it is one of the reasons why it is good to use various compilers to see how the same code runs (or doesn't) under different conditions.

Quote:
The cplusplus.com reference on operator>> has a section on "manipulators which have an effect when used on standard istream objects"

From above reference...
http://www.cplusplus.com/reference/iostream/istream/operator>>/
The manipulators which have an effect when used on standard istream objects are:

boolalpha Alphanumerical bool values (manipulator function)
noboolalpha No alphanumerical bool values (manipulator function)
skipws Skip whitespaces (manipulator function)
noskipws Do not skip whitespaces (manipulator function)
dec Use decimal base (manipulator function)
hex Use hexadecimal base (manipulator function)
oct Use octal base (manipulator function)
ws Extract whitespaces (manipulator function)

Other manipulators may be applicable to standard istream objects, but have no effect.

Also see this comp.lang.c++ discussion (this one too)

Also, see this output. Output is from compiling with vs2008, but same code and same results with g++ 3.4.3 (tested on program.cs.fsu.edu)

This is my output from ex 15.7: I've tested this on both VS2008 and g++ 3.4.3



First three lines of input:

int n[3];

cout << "Enter decimal: ";
cin >> dec >> n[0];
cout << "Enter octal: ";
cin >> oct >> n[1];
cout << "Enter hexadecimal: ";
cin >> hex >> n[2];

I'm not using borland, so I can't say that cin >> showbase doesn't work with that compiler, but it doesn't work with visual studio 2008 or g++ 3.4.3

This simple case (at least on vs2008 and g++ 3.4.3) shows this:

#include <iostream>

int main()
{
int x;

ctd::cout << "Enter number: ";
std::cin >> std::showbase >> x;
std::cout << "You entered: " << x;
}



I've presented my case for using hex, dec, and oct modifiers and why cin >> showbase does not work. If I'm wrong, I'm wrong, but I don't think I am.

Quote: Original post by curtmax_0
Don't argue with your professor. Just get a good grade and move on.

Quote: You aren't helping anyone.

Quote: Your professor won't care

Quote: the other students won't believe you,

Quote: I had one class where I corrected the instructor after every lecture. I was nice about it too. I never confronted her while other students were there and just showed her in the C standard and whatnot how she was wrong. She hated me for it. I still received an A since all the tests were multiple choice... so she couldn't take BS points off.

Quote: Original post by curtmax_0
Don't argue with your professor. Just get a good grade and move on. You aren't helping anyone. Your professor won't care, the other students won't believe you, and you won't help yourself grade-wise.

Quote:


Using showbase (Boland 5.5 and VS.NET 2003), and the following code works:

cin >> showbase >> i;

#include <iostream>using std::cout;using std::cin;using std::endl;using std::showbase;using std::hex;using std::oct;using std::dec;int main(){	int d,o,h;		cout << "Decimal: ";	cin >> showbase >> d;		cout << showbase;		cout << "OUTPUT AS..." << endl;	cout << "Hex: " << hex << d << endl;	cout << "Oct: " << oct << d << endl << endl;		cout << "Octal: ";	cin >> showbase >> o;		cout << "OUTPUT AS..." << endl;	cout << "Hex: " << hex << o << endl;	cout << "Dec: " << dec << o << endl << endl;		cout << "Hex: ";	cin >> showbase >> h;		cout << "OUTPUT AS..." << endl;	cout << "Dec: " << dec << h << endl;	cout << "Oct: " << oct << h << endl << endl;}