OCA JAVA - 2 Programming with Java Statements
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The document provides a comprehensive overview of programming with Java, focusing on key concepts such as assignment, conditional, iteration, and transfer of control statements. It explains how assignment statements set values to variables, the use of conditional statements for flow control, different types of iteration statements for code repetition, and the purpose of transfer control statements to manage program execution flow. Each section includes definitions, examples, and syntax to aid understanding of Java programming techniques.
OCA JAVA - 2 Programming with Java Statements
- 1. 2. Programming with Java Statements • Understanding Assignment Statements • Understanding Conditional Statements • Understanding Iteration Statements • Understanding Transfer of Control Statements By Fernando Gil Date: Jan 2015 Version: 1.0 Based in the book OCA Java SE 7 Programmer I Study Guide (Examn 1Z0-803)
- 2. 1. Understanding Assignment Statements • An assignment statement sets a value within a variable • All assignment are considered to be expression statements • Expressions in Java are anything that has a value • Typically, expressions evaluate to primitive types Expression Statement Example Assignment variable = 7 Pre-increment ++variable; Pre-decrement --variable; Post-increment variable++; Post-decrement variable--; Method invocation variable = performMethod(); Object creation variable = new ClassName();
- 3. The Assignment Expression Statements • Commonly known simply as assignment statements, are designed to assign values to variables and must be terminated with a semicolon Variable = value; • On the left is the variable that will be associated with the memory and type necessary to store the value. On the right is a literal value.
- 4. 2. Understanding Conditional Statements • Conditional statements are used when there is a need for determining the direction of flow based on conditions
- 5. The if conditional Statement • The if statement is designed to conditionally execute a statement or conditionally decide between a choice of statements • The if statement will execute only one statement upon the condition, unless braces are supplied. Braces allow for multiple enclosed statements to be executed. This group of statements is also known as a block • The expression that is evaluated within if statements must evaluate to a boolean value • The else clause is optional and may be omitted
- 7. The if-then conditional Statement • The if-then statement is used when multiple conditions need to flow through a decision-based scenario
- 8. The if-then-else conditional Statement • The main difference is that the code will fall through to the final stand-alone else when the expression fails to return true for any condition
- 9. The switch conditional Statement • It is used to match the value from a switch statement expression against a value associated with a case keyword. Once matched, the enclosed statements associated with the matching case value are executed, unless a break statement is encountered • The break statements are optional and will cause the immediate termination of the switch conditional statement • The expression of the switch statement must evaluate to byte, short, int, char, string
- 11. 3. Understanding Iteration Statements • Iteration statements are used when there is a need to iterate through pieces of code • Iteration statements include for loop, enhanced for loop, and the while and do-while statements. • The continue statement is used to terminate the current iteration and continue with the next iteration • The break statement is used to exit the body of any iteration statement
- 12. The for loop Iteration Statement • It has many parts that include an initialization part, an expression part, and an iteration part • The initialization does not need to declare a variable as long as the variable is declared before the for statement. So int x=0 and x=0 are both acceptable • The expression within the for loop must be evaluated to a boolean value • The iteration, also known as the update part, provides the mechanism that will allow the iteration to occur
- 14. The enhanced for loop Iteration Statement • It is used to iterate through an array, a collection, or an object that implements the interface iterable. • It is also commonly known as the for each loop • Here is the general usage of the for each statement: for (type variable : collection)
- 15. The while Iteration Statement • This loop evaluates an expression and executes the loop body only if the expression evaluates to true • There is typically an expression within the body that will affect the result of the expression
- 16. The do-while Iteration Statement • It is very similar to the while loop, except that it always executes the body at least once • The do-while loop evaluates an expression and continues to execute the body only if it evaluates to true
- 17. 4. Understanding Transfer of Control Statements • The transfer of control statements provide a means to stop or interrupt the normal flow of control • They are always used within other types of statements • Transfer of control statements include the break, continue and return statements
- 18. The break Transfer of Control Statement • It is used to exit or force an abrupt termination of the body of the conditional and iteration statements
- 19. The continue Transfer of Control Statement • It is used to terminate the current iteration of a loop and continue with the next iteration
- 20. The return Transfer of Control Statement • It is used to exit a method and optionally return a specified value as an expression • A return statement with no return value must have the keyword void in the method declaration
- 22. 3. Programming with Java Operators Next Slide: