C++ bit testing

While my power was out :p
I had alot of time to read, so here is a clean C++ way of testing bits.

Code:

---

#include <iostream>
#include <bitset>  // Include the bitset header

int main ( void )
{
       
    // Set the container
    // Since I'm testing a single byte you want the size to be 8
    // You can change this to the bit size of the variable your testing
    std::bitset<8> flags;

    // Value to test       
    unsigned char value = 0x3D;

    // Set the flags
    flags |= value;

    // Display the binary number
    std::cout << flags << std::endl;

    // The bits are stored in an array -----------
    // You can test each one ---------------------
    for ( int loop = 0; loop < 8; loop++ ) {

        if ( flags[loop] )
            std::cout << "Flag " << loop << " is set" << std::endl;


        else std::cout << "Flag " << loop << " is not set" << std::endl;

    }
    // -------------------------------------------
    // -------------------------------------------

    return 0;

}

---

:)

I suggest to place this in FAQ section!

Or you could use the & operator without using the bitset class:

Code:

---

#include <iostream>


int main()
{
int value = 61;
for (int i=1,loop=0;i<=value;i*=2,loop++)
  if (value&i)
    std::cout<<"Bit "<<loop<<" is set."<<std::endl;

std::cin.get();
}

---

But it would be more difficult to output the value in binary...

Quote:

---

Originally Posted by JaWiB

But it would be more difficult to output the value in binary...

---

Not really

Code:

---

#include <iostream>

int main ( void )
{

    unsigned char value = 0x3D;

    for ( int loop = 7; loop >= 0; loop-- ) {

        int the_bit = (value >> loop) & 1;
        std::cout << the_bit;

    }

    return 0;

}

---

;)

And that would also work with C.

I just found that the C++ bitset class was a really simple method to dispay, test, and manipulate bits.