3D. Expressions

You should be familiar with expressions from algebra. You evaluate an expression, and the evaluation yields a value. For example, evaluating expression 2 + 5 yields value 7.

C++ and Java support the same arithmetic operators, including

• + (addition),
• - (subtraction or negation),
• * (multiplication),
• / (division) and
• % (remainder in integer division).

See more detail on elementary C++ expressions.

Watch out. Division of integers always produces an integer result. Everything after the decimal point is thrown away. The value of C++ expression 5/3 is 1.

Precedence

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Binary operators *, / and % have higher precedence than + and -. For example, expression 1 + 2 * 3 has value 7, since the multiplication is done first. Use parentheses to force the order of evaluation. Expression (1 + 2) * 3 has value 9.

Binary operators listed above that have the same precedence are done from left to right. So expression 5 - 2 - 1 has value 2.

See more detail on operator precedence and order of evaluation.

Exercises

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1. What is the value of C++ expression 5-1-1? Answer

2. What is the value of expression 5/4? Answer

3. What is the value of expression 9/5? Answer

4. What is the value of expression 9%5? Answer

5. What is the value of expression 12/2*2? Answer