Review

CST200 – Week 7: Common Mistakes in the First two Midterms

Instructor: Andreea Molnar

Outline

•Division

•Escape Sequences

•String Methods

Division

% (remainder operator, modulus operator) - returns the remainder after dividing the second operand to the first

19 % 4 = 3

4 % 9 = 4

Division

% - the sign of the result is the sign of the numerator (first operand)

-10 % 3 = -1

10 % -3 = 1

Division

/ - results depend on the type of the operand

• if both operands are integers (byte, short, int, long) the result is integer, any fractional part of the result is discarded

• if either or both operands are floating point (float, double) the result is floating point

Division14 / 5 = 2

14.0 / 5 = 2.8

14 / 5.0 = 2.8

14.0 / 5.0 = 2.8

(double) 14 / 5 = 2.8

(double) (14 / 5) = 2.0 // in this case the integer division is performed first and afterwards the type casting

Escape SequencesEscape sequence Meaning

\b backspace

\t tab

\n newline

\r return

\’’ double quote

\’ single quote

\\ backslash

Escape SequencesString firstName = "Mary";

String lastName = "Smith";

System.out.println(firstName + "\t" + lastName);

Mary Smith

System.out.println(firstName + "\n" + lastName);

Mary

Smith

System.out.println(firstName + "\"" + lastName);

Mary"Smith

System.out.println(firstName + "\\" + lastName);

Mary\Smith

String Methods

String substring(int beginIndex, int endIndex)

returns a substring that begins at the beginIndex and ends at the endIndex -1

String str = “Arizona State University”;

str.substring (3, 5); //substring that begins at the index 3 (z) and ends at the 5-1 (o) zo

String Methods

String indexOf (String str)

returns the index of the first occurrence of str

if multiple occurrences returns just the first one

String str = “Arizona State University”;

str.substring (“i”); //2

Best of luck with the exam!