CMPT 120 Lecture Notes - Lecture 9: Concatenation, String Operations, Order Of Operations

• School: Simon Fraser University
• Department: Computing Science
• Course: CMPT 120
• Professor: Liaqat Ali

Document Summary

Lecture 9 part 5: i/o functions, types, operator precedence, string operations. When an expression contains more than one operator, the order of evaluation depends on the order of operations. The acronym pemdas is a useful way to remember the rules: Parentheses have the highest precedence and can be used to force an expression to evaluate in the order you want. Expressions in parentheses are evaluated first, 2 * (3-1) is 4, and (1+1)**(5-2) is 8. You can also use parentheses to make an expression easier to read, even if it doesn"t change the result. Exponentiation has the next highest precedence, so: 1 + 2**3 is 9, not 27, and 2*3**2 is. Multiplication and division have higher precedence than addition and subtraction. 2*3-1 is 5, not 4, and 6+4/2 is 8, not 5. Operators with the same precedence are evaluated from left to right (except exponentiation).