CPSC 233 - Introduction to Computer Science

for Computer Science Majors II

Tutorials: MW 3-3.50 MS 176

CT hours: Wednesday 5-6pm, Friday 12-3pm

TA: Monir Zaman

(Md Moniruzzaman)

Variable declarations

int number2, number1;

float leng= 3.4f;

double diam=54.3;

number2 = number1 = 3;

long num3=789l;

print methods

double price = 19.8;

System.out.print("$");

System.out.printf("%f", price);

System.out.println("each");

will output the line

$19.80each

printf Format Specifier

• The code double price = 19.8;

System.out.print("$");

System.out.printf("%6.2f", price);

System.out.println(" each");

will output the line $ 19.80 each

2-4 Copyright © 2012 Pearson Addison-Wesley. All rights

reserved.

Right and Left Justification in printf

• The code double value = 12.123;

System.out.printf("Start%8.2fEnd", value);

System.out.println();

System.out.printf("Start%-8.2fEnd", value);

System.out.println();

will output the following

Start 12.12End

Start12.12 End

2-5 Copyright © 2012 Pearson Addison-Wesley. All rights

reserved.

Multiple arguments with printf

• What is the output of the following code:

double price = 19.8;

String name = "magic apple";

System.out.printf("$%6.2f for each %s. \n" , price, name);

System.out.println("Wow");

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reserved.

String variables

• Store text

String name=“John”;

String name=null;

String name;

String

String name=“John”;

name.equals(“smith”)

Returns a boolean value: true/false

String name1=“John”;

String name2=“Smith”;

If( name1.equals(name2) ) {

System.out.printf(“Names %s and %s are equal”, name1, name2);

}

String

String name=“John”;

name.equalsIgnoreCase(“joHn”)

Returns a boolean value: true

Method definition

boolean equals (String)

boolean equalsIgnoreCase (String)

String toUpperCase()

String toLowerCase()

String toUpperCase()

String toLowerCase()

Example:

String a_b=“stat101”;

System.out.println(a_b.toUpperCase());

STAT101

Some Methods in the Class String (Part 4 of 8)

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reserved.

Some Methods in the Class String (Part 5 of 8)

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reserved.

String: immutable type

• Individual characters of a string can not be changed like we can for Arrays

• StringBuffer supports changing individual char

• No mutator method is defined in String class

• String is defined as a immutable to prevent privacy leak

String s1 = "First string"; String s2 = s1; s1 = s1 + "!";

Exercise

• Write a program that has a string variable containing a line of text and then outputs that line with the first occurrence of “hate” changed to “love”. A sample output of the program:

String value: I hate strong wind. Correct output: I love strong wind. You can have the word “hate” more than once in the line but change only its first occurrence.

Thanks