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![class operators {
public static void main(String[] args) {
System.out.println("nBitwise operators nn") ;
System.out.println(" 2 & 3 = " + ( 2 & 3 ) + " bitwise AND ") ;
System.out.println(" -2 & 3 = " + (-2 & 3 ) ) ;
System.out.println(" 2 | 3 = " + ( 2 | 3 ) + " bitwise OR ") ;
System.out.println(" -2 | 3 = " + (-2 | 3 ) ) ;
System.out.println(" 2 ^ 3 = " + ( 2^3) + " bitwise Exclusive OR" ) ;
System.out.println(" -2 ^ 3 = " + (-2^3) ) ;
System.out.println(" 10 << 2 " + ( 10 << 2) ) ;
System.out.println(" 10 >> 2 " + ( 10 >> 2) ) ;
System.out.println("-10 << 2 " + (-10 << 2) ) ;
System.out.println("-10 >> 2 " + (-10 >> 2) ) ;
System.out.println(" 10 >>> 2 " + ( 10 >>> 2) ) ;
System.out.println("-10 >>> 2 " + (-10 >>> 2) ) ;
}
}
19](https://image.slidesharecdn.com/chapter23javafundamentalsandcontrolstructures-230928040557-e7395588/85/Chapter-2-3-java-fundamentals-and-Control-Structures-ppt-19-320.jpg)
![For-each Loop example
double[] ar = {1.2, 3.0, 0.8};
int sum = 0;
/* d gets successively each
value in ar */
for (double d : ar)
{.
sum += d;
}
double[] ar = {1.2, 3.0, 0.8};
int sum = 0;
/* i indexes each element
successively. */
for (int i = 0; i < ar.length; i++) {
Sum += ar[i];
}
•The for-each loop is used to access each successive
value in a collection of values.
•Here is a loop written as both a for-each loop and a
basic for loop to add all elements of an array
44](https://image.slidesharecdn.com/chapter23javafundamentalsandcontrolstructures-230928040557-e7395588/85/Chapter-2-3-java-fundamentals-and-Control-Structures-ppt-44-320.jpg)
![Nested for loop…
import javax.swing.JOptionPane;
public class TestMultiplicationTable {
/** Main method */
public static void main(String[] args) {
// Display the table heading
String output = " Multiplication Tablen";
output += "-------------------------------------------------n";
// Display the number title
output += " | ";
for (int j = 1; j <= 9; j++)
output += " " + j;
output += "n";
46](https://image.slidesharecdn.com/chapter23javafundamentalsandcontrolstructures-230928040557-e7395588/85/Chapter-2-3-java-fundamentals-and-Control-Structures-ppt-46-320.jpg)
Chapter 2&3 (java fundamentals and Control Structures).ppt
- 1. Java Fundamental and ControlStructures Object-Oriented Programming 1
- 2. Identifiers Variables Constants Primitive Data Types Operators Expressions Control Flow Selection Statements Looping statements break and continue Statements Agenda 2
- 3. An identifieris a sequence of characters that consist of letters, digits, underscores (_), and dollar signs ($). An identifier must start with a letter, an underscore (_), or a dollar sign ($). It cannot start with a digit. An identifier cannot be a reserved word. An identifier cannot be true, false, or null. An identifier can be of any length. Identifiers can be variables or constants 3 Identifiers
- 4. • Global variable,local variables • Instance variable, static variable • Variable Declaration – int x; – double radius; – char a; • Variable Declaration – X=5; – Radius = 2.7 – a = ‘C’ • Declaring and Initializing can be done in one Step – int x = 1 – String str = “Hi”; – boolean b = (1 > 2); Variable Declaration and initialization 4
- 5. The valuesof constants can never be changed once they are initialized. Constant variables are also called named constants or read-only variables. The general formal for declaration of constants is given by: final datatype CONSTANTNAME = VALUE; Examples final double PI = 3.14159; final int SIZE = 3; Math.PI (built in constant) 5 Constants
- 6. • String literal –sequence of characters in double quotation marks. E.g. “Java” • floating-point literals – E.g. 34.678 • Integer literal – E.g. 45 • Character literal – E.g. ‘A’ Literal Values 6
- 7. Are reservedfor use by Java and are always spelled with all lowercase letters. Keywords 7
- 8. There arearound 8 primitive data types in java. These are byte short int long float double boolean char Primitive Data Type 8
- 9. Name Range StorageSize byte –27 (-128) to 27–1 (127) 8-bit signed short –215 (-32768) to 215–1 (32767) 16-bit signed int –231 (-2147483648) to 231–1 (2147483647) 32-bit signed long –263 to 263–1 64-bit signed (i.e., -9223372036854775808 to 9223372036854775807) float Negative range: 32-bit IEEE 754 -3.4028235E+38 to -1.4E-45 Positive range: 1.4E-45 to 3.4028235E+38 double Negative range: 64-bit IEEE 754 -1.7976931348623157E+308 to -4.9E-324 Positive range: 4.9E-324 to 1.7976931348623157E+308 Numeric Data Type 9
- 10. Is convertingfrom one data type to another conversions that may lose precision conversions without information loss Legal conversions between numeric types Casting 10
- 11. The castoperator can be used to convert between primitive numeric types, such as int and double, and between related reference types The syntax for casting is to give the target type in parentheses, followed by the variable name. E.g. double x =9.997; int nx = (int) x; nx is now 9 Double x = 9.997; int nx = (int) Math.round(x); nx is now 10 int i = 'a'; // Same as int i = (int)'a'; char c = 97; // Same as char c = (char)97; Casting to the wrong type may cause compilation errors or runtime errors. Casting… 11
- 12. • Arithmetic operators –+ (addition) – – (subtraction) – * (multiplication) – / (division) • Integer division by zero is not allowed where as floating-point division by zero yields an infinite. Java Operator 12
- 13. Increment andDecrement operators ++ adds 1 to the current value of the variable . -- subtracts 1 from the variable. Variants: postfix and prefix E.g. ++m and n++ What is the output of char ch = 'a‘; System.out.println(++ch); Java Operator… 13
- 14. • Assignment operator Used to assign value to a variable. E.g. int x=34; • Compound Assignments Java Operator… 14
- 15. Logical operators –&& for the logical “and” operator and – || for the logical “or” operator Boolean logical operators – & and | are identical to && and || respectively except • Boolean logical operator s always evaluate both of their operands (i.e. they don’t perform short-circuit evaluation) If x is 1, what is x after this expression? (x > 1) & (x++ < 10) If x is 1, what is x after this expression? (1 > x) && ( 1 > x++) How about (1 == x) | (10 > x++)? (1 == x) || (10 > x++)? – Boolean logical exclusive OR(^) – Logical Negation (!) Operator Java Operator… 15
- 16. Relational operators • ==(equal), • != (not equal) • < (less than), • > (greater than), • <= (less than or equal), and • >= (greater than or equal) operators. Java Operator… 16
- 17. Bitwise Operators • Whenworking with any of the integer types, you have operators that can work directly with the bits that make up the integers. • Some bitwise operators are • & (“and”) • | (“or”) • ^ (“xor”) • ~ (“not”) e.g. used to get one’s complement of a number. • What are the others? Java Operator… 17
- 18. Operator Meaning & BitwiseAND | Bitwise OR ^ Bitwise XOR << Left shift >> Right shift >>> Zero fill right shift ~ Bitwise complement <<= Left shift assignment (x = x << y) >>= Right shift assignment (x = x >> y) >>>= Zero fill right shift assignment (x = x >>> y) x&=y AND assignment (x = x & y) x|=y OR assignment (x = x | y) x^=y XOR assignment (x = x ^ y) 18
- 19. class operators { publicstatic void main(String[] args) { System.out.println("nBitwise operators nn") ; System.out.println(" 2 & 3 = " + ( 2 & 3 ) + " bitwise AND ") ; System.out.println(" -2 & 3 = " + (-2 & 3 ) ) ; System.out.println(" 2 | 3 = " + ( 2 | 3 ) + " bitwise OR ") ; System.out.println(" -2 | 3 = " + (-2 | 3 ) ) ; System.out.println(" 2 ^ 3 = " + ( 2^3) + " bitwise Exclusive OR" ) ; System.out.println(" -2 ^ 3 = " + (-2^3) ) ; System.out.println(" 10 << 2 " + ( 10 << 2) ) ; System.out.println(" 10 >> 2 " + ( 10 >> 2) ) ; System.out.println("-10 << 2 " + (-10 << 2) ) ; System.out.println("-10 >> 2 " + (-10 >> 2) ) ; System.out.println(" 10 >>> 2 " + ( 10 >>> 2) ) ; System.out.println("-10 >>> 2 " + (-10 >>> 2) ) ; } } 19
- 20. Conditional Operator(?:) is the Java’s only ternary operator - that means it takes three operands The first operand is Boolean expression Either the second or the third operand is executed based on the value of the first operand E.g. System.out.println(Grade>=60?”Passed”:”Failed” Max = X > Y ? X : Y The new Operator – Is used to create an object or instance from a class. – E.g. Scanner s=new Scanner(System.in); DataInputStream str=new DataInputStream (System.in); Java Operator… 20
- 21. var++, var-- +, - (Unary plus and minus), ++var,--var (type) Casting ! (Not) *, /, % (Multiplication, division, and remainder) +, - (Binary addition and subtraction) <, <=, >, >= (Comparison) ==, !=; (Equality) & (Unconditional AND) ^ (Exclusive OR) | (Unconditional OR) && (Conditional AND) Short-circuit AND || (Conditional OR) Short-circuit OR =, +=, -=, *=, /=, %= (Assignment operator) 21 Java Operator…
- 22. An expressionis any legal combination of symbols that represents a value. Each programming language and application has its own rules for what is legal and illegal. In Java, arithmetic, boolean, and String expressions are written in conventional mathematical infix notation Examples of valid expressions in java are var X+1 “string” 5 ! (5 < 6) (x*x + y*y > 25) && (x > 0) Expressions 22
- 23. There arethree basic types of program flows Sequential In Sequential execution statements in a program are executed one after the other in sequence. Selection Selection or conditional execution executes part of the code based on the condition Iteration In iterative program flow statements inside looping statement are executed repeatedly as long as a condition is true Control Flows 23
- 24. Java hasthe following Conditional statements if Conditions if Statement If…else Statement if …else if…else Statement Conditional Operators (?:) switch Statements Selection/conditional Statement 24
- 25. if (booleanExpression) { statement(s); } 25 Boolean Expression true Statement(s) false (radius>= 0) true area = radius * radius * PI; System.out.println("The area for the circle of " + "radius " + radius + " is " + area); false (A) (B) if (radius >= 0) { area = radius * radius * PI; System.out.println("The area" + " for the circle of radius " + radius + " is " + area); } if Statements
- 26. These selectionstatement is used if there are exactly two selections Syntax: if (booleanExpression) { statement(s)-for-the-true-case; } else { statement(s)-for-the-false-case; } 26 Boolean Expression false true Statement(s) for the false case Statement(s) for the true case The if...else Statement
- 27. if (radius >=0) { area = radius * radius * 3.14159; System.out.println("The area for the “ + “circle of radius " + radius + " is " + area); } else { System.out.println("Negative input"); } 27 The if...else Statement, example
- 28. Conditional statementcan be used instead of if…else statement if (x > 0) y = 1 else y = -1; is equivalent to y = (x > 0) ? 1 : -1; Syntax (booleanExp) ? exp1 : exp2 Conditional Operators (?:) 28
- 29. if…else if…elsestatement is important if there are more than two conditions Syntax: if (booleanExpression) { statement(s); } else if (booleanExpression){ statement(s); } … else { statement(s); } if …else if…else Statement 29
- 30. 30 if …else if…elseStatement, example •The following code snippet depicts how nested if else statement is used to calculate letter grade from a score out of 100
- 31. The examplein preceding slide can be done by using sequence of if statements if (score>=90) grade =‘A’ if (score>=80) grade = “B” if (score >=70) grade = ‘C’ if (score>=60) grade = ‘D’ … …. if …else if…else Statement, example 31
- 32. Problem: Writea program that solves quadratic equation if …else if…else Statement, example 32
- 33. The if/elseconstruct can be cumbersome when you have to deal with multiple selections with many alternatives. E.g. To set up Menu System Syntax switch (switch-expression) { case value1: statement(s)1; break; case value2: statement(s)2; break; … case valueN: statement(s)N; break; default: statement(s)-for-default; } switch Statements 33
- 34. switch Statements flowchart Case 1 Statement(s) break Statement(s) break Case 2 Statement(s) break sCase 3 Statement(s) break Case N Statement(s) default Next Statement 34
- 35. The switch-expressionmust yield a value of char, byte, short, or int type and must always be enclosed in parentheses. The value1, ..., and valueN must have the same data type as the value of the switch-expression. The resulting statements in the case statement are executed when the value in the case statement matches the value of the switch-expression. Note that value1, ..., and valueN are constant expressions, meaning that they cannot contain variables in the expression, such as 1 + x. switch Statements… 35
- 36. The keywordbreak is optional, but it should be used at the end of each case in order to terminate the remainder of the switch statement. If the break statement is not present, the next case statement will be executed. The default case, which is optional, can be used to perform actions when none of the specified cases matches the switch-expression. The case statements are executed in sequential order, but the order of the cases (including the default case) does not matter. However, it is good programming style to follow the logical sequence of the cases and place the default case at the end. switch Statements… 36
- 37. Write ajava program that converts students score to letter grade using switch statement int Choice = score/10 switch(choice){ case 9: grade = ‘A’; break; case 8: grade = ‘B’; break; case 7: grade = ‘C’; break; switch Statements, Example case 5: case 4: case 3: case 2: case 1: case 0: grade = 'F'; break; default: System.out.println("Invalid score"); } 37
- 38. Java havethe following repitition statements while loop do…while loop for loop for each loop Repetition Statement 38
- 39. while Loop Syntax: while (loop-continuation- condition){ Statement(s); increment; } int count = 0; while (count < 100) { System.out.println("Welcome to Java!"); count++; } Loop Continuation Condition? true Statement(s) (loop body) false (count < 100)? true System.out.println("Welcome to Java!"); count++; false (A) (B) count = 0; 39
- 40. do-while Loop Syntax: do { //Loop body; Statement(s); } while (condition); Loop Continuation Condition? true Statement(s) (loop body) false Note that in do while loop the body of the loop is executed at least once 40
- 41. Syntax for (initialization; loopContinuationCondition; increment ) { Statement (s); } For loop 41
- 42. Multiple initializationand increments are allowed For loop… 42
- 43. The basicfor loop was extended in Java 5 to make iteration over arrays and other collections more convenient. This newer for statement is called the enhanced for or for-each (because it is called this in other programming languages). For-each Loop 43
- 44. For-each Loop example double[]ar = {1.2, 3.0, 0.8}; int sum = 0; /* d gets successively each value in ar */ for (double d : ar) {. sum += d; } double[] ar = {1.2, 3.0, 0.8}; int sum = 0; /* i indexes each element successively. */ for (int i = 0; i < ar.length; i++) { Sum += ar[i]; } •The for-each loop is used to access each successive value in a collection of values. •Here is a loop written as both a for-each loop and a basic for loop to add all elements of an array 44
- 45. Problem: Writea program that uses nested for loops to print a multiplication table. Output: should look like Nested for loop 45
- 46. Nested for loop… importjavax.swing.JOptionPane; public class TestMultiplicationTable { /** Main method */ public static void main(String[] args) { // Display the table heading String output = " Multiplication Tablen"; output += "-------------------------------------------------n"; // Display the number title output += " | "; for (int j = 1; j <= 9; j++) output += " " + j; output += "n"; 46
- 47. Nested for loop… //Print table body for (int i = 1; i <= 9; i++) { output += i + " | "; for (int j = 1; j <= 9; j++) { // Display the product and align properly if (i * j < 10) output += " " + i * j; else output += " " + i * j; } output += "n"; } // Display result JOptionPane.showMessageDialog(null, output); } } 47
- 48. break in switch statements repetition statements. The break statement, when executed in a while, for, do…while or switch, causes immediate exit from that statement. break and continue Statements 48
- 49. Problem: Writea program that finds out all prime numbers less than a number entered from a keyboard Example boolean status; Scanner input = new Scanner(System.in); System.out.println("Enter a number"); int max = input.nextInt(); System.out.println("Prime numbers"); for(int i = 2; i<=max;i++){ status = true; for(int j=2;j<i ; j++){ if (i/j ==0){ status =false; continue; } } if(status) System.out.println(i); } 49
- 50.