Creating Calculators with Operators - Learn C++ for Game Development - page 29

In the 8s column we have a 1 in first and a 1 in second; therefore the result bit is 1.

In the 16s column we have a 0 in first and a 1 in second; therefore the result bit is 0.

All other columns have 0s in both values.

As you can see, to be able to have a 1 in a bit column in our result value the corresponding bit
column also had to be 1 in the first and second values. If either of the values was a 0 then the result
bit at the same column is also a 0.

The Binary | (OR) Operator
The Bitwise | , or OR, operator is used to determine if either of the bits in a given column is set to
1 in either of the two supplied values. Table 3-3 shows the result of using | with the same 0x0F and
0x18 values as the previous example.

Table 3-3. The Result of Using Bitwise | on 0x0F and 0x18

128 64 32 16 8 4 2 1

first 0 0 0 0 1 1 1 1

second 0 0 0 1 1 0 0 0

ord 0 0 0 1 1 1 1 1

The result of the | on the two values is 0x1F. We derived this using the following method from
left to right.

In the 1s column we have a 1 in first; therefore the result bit is 1.

In the 2s column we have a 1 in first; therefore the result bit is 1.

In the 4s column we have a 1 in first; therefore the result bit is 1.

In the 8s column we have a 1 in first; therefore the result bit is 1.

In the 16s column we have a 1 in second; therefore the result bit is 1.

All other columns have 0s in both values.
Using the | operator is as simple as using the & operator; however, the resulting bit for each column
is set to 1 if either of the bits from the two input values were 1.

The Binary ^ (Exclusive OR) Operator
Our last bitwise operator is the ^ (or Exclusive OR/XOR) operator. This operator differs from the |
operator by requiring that one of the two input values bits is set, but not both. Table 3-4 shows this
in practice.