2.5. Arithmetic

Most programs perform arithmetic calculations. Figure 2.6 summarizes the C++ arithmetic operators. The asterisk (*) indicates multiplication and the percent sign (%) is the modulus operator that will be discussed shortly. The arithmetic operators in Fig. 2.6 are all binary operators, i.e., operators that take two operands. For example, the expression number1 + number2 contains the binary operator + and the two operands number1 and number2.

Fig. 2.6. Arithmetic operators.

Integer division (i.e., where both the numerator and the denominator are integers) yields an integer quotient; for example, the expression 7 / 4 evaluates to 1 and the expression 17 / 5 evaluates to 3. Any fractional part in integer division is truncated—no rounding occurs.

C++ provides the modulus operator, %, that yields the remainder after integer division. The modulus operator can be used only with integer operands. The expression x % y yields the remainder after x is divided by y. Thus, 7 % 4 yields 3 and 17 % 5 yields 2. In later chapters, we discuss many interesting applications of the modulus operator, such as determining whether one number is a multiple of another (a special case of this is determining whether a number is odd or even).