How to Check a Bit\'s Status Without Shifting or Masking?

Verifying Bit Status Without Shifting or Masking

When manipulating bits, it's often necessary to check the status of a specific bit within an integer variable. Consider the following example:

int temp = 0x5E; // in binary 0b1011110

We want to determine if bit 3 in the binary representation of temp is set to 1 or 0.

Builtin Function?

The question arises: is there a built-in function that performs this operation without resorting to bit shifting and masking?

Custom Macro in C

In C, there is no native solution. However, you can create a macro to simplify the process:

#define CHECK_BIT(var,pos) ((var) & (1<<(pos)))

where var is the integer to be checked and pos is the bit position (0-indexed, starting from the rightmost bit).

To check the 3rd bit from the right end:

CHECK_BIT(temp, 2)

Std::bitset in C

In C , you can leverage the std::bitset class:

std::bitset<32> bits(temp);
if (bits.test(3)) {
  // Bit 3 is set
}

Here, bits represents the binary representation of temp and bits.test(3) checks the value of the 3rd bit.

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