Strings and Class Type

Strings and Class Type

AP CSA

Class data types are capitalized, and primitive data types are not

Primitive data types only hold one piece of data at a time



Multiple Choice

int x=15; is :

• primitive type

• class type

Multiple Choice

True or False: Variables of class data types do not always have to hold a memory location all the time

• True

• False

When a group of statements, including control structures are assembled into a single unit, the unit is called a class

Naming conventions are similar to those of a variable but a class should begin with a capital letter and reference the purpose of the class.

public class GradePointAvg

{

// statements not shown

}

Multiple Choice

Which of the following class declarations would cause a compile-time error? Assume the rest of the code compiles as intended.

• public class Science

• public class apScience

• public class APScience

• public class 4APScience

• public class APScience extends Science

A Java string is a series of characters gathered together, like the word "Hello", or the phrase The expert in anything was once a beginner — Helen Hayes.

The standard way to create a new object of a class in Java:

greeting = new String("Hello");

You can also use just a string literal, which is a set of characters enclosed in double quotes ("), to create a String object.

greeting = "Hello";

Strings can be appended to each other to create a new string using the + or += operator .

This is also called concatenation.

  String start = "Happy Birthday";

    String name = "Jose";

    String result = start + " " + name; // add together strings

Multiple Choice

Which of the following statements use string literal?

• System.out.print(side1);

• System.out.print("side1");

Numerical values can be printed to the screen for output

• Example: If a triangle has a side length of 2 stored in memory using identifies side1 and you eant to ouput that information to the screen you could use either:

• System.out.print(2);

• System.out.print(side1): //will display the value stored using the side1 identifier

• System.out.print("side 1") // will display

Multiple Choice

Assuming all other statements in the program are correct, each of the following statements will allow the program to compile EXCEPT:

• System.out.print(2);

• System.out.print("2");

• System.out.print(side1);

• System.out.print("side1");

Don't forget to look at activites on coding bat for addtional practice.

(6 min)

https://codingbat.com/doc/java-string-introduction.html

https://youtu.be/xqFGn5P1Ho8