An assignment simply stores a value in a variable and has the
<variable> = <expression>;
An expression can be a simple value but can also be more complicated, so, rather than assigning a value to a variable, one can also add a value to the current value of the variable using +=, for example:
a += b;
Similarly, you can subtract it using -=, multiply it using *=, divide it using /=, or use bitwise operators using |=, &=, or ^=. You can also add or subtract one from a value using ++, --.