An operator is a symbol that causes the compiler to take an action. Operators act on operands, and in C++ all operands are expressions. In...
An operator is a symbol that causes the compiler to take an action. Operators act on operands, and in C++ all operands are expressions. In C++ there are several different categories of operators. Two of these categories are
- Assignment operators.
- Mathematical operators.
- Increment and Decrement Operators
- Relational Operators
Assignment Operator
The assignment operator (=) causes the operand on the left side of the assignment operator to have its value changed to the value on the right side of the assignment operator. The expression
x = a + b;
assigns the value that is the result of adding a and b to the operand x.
An operand that legally can be on the left side of an assignment operator is called an lvalue. That which can be on the right side is called (you guessed it) an rvalue.
Constants are r-values. They cannot be l-values. Thus, you can write
x = 35; // ok
but you can't legally write
35 = x; // error, not an lvalue!
New Term: An lvalue is an operand that can be on the left side of an expression. An rvalue is an operand that can be on the right side of an expression. Note that all l-values are r-values, but not all r-values are l-values. An example of an rvalue that is not an lvalue is a literal. Thus, you can write x = 5;, but you cannot write 5 = x;.
