NLPAI Java Lecture No 4 Operators Decision Constructs

  • Slides: 12
Download presentation
NLP-AI Java Lecture No. 4 Operators & Decision Constructs Satish Dethe <satishd@cse. iitb. ac.

NLP-AI Java Lecture No. 4 Operators & Decision Constructs Satish Dethe <[email protected] iitb. ac. in> 03 August 2004

Contents • Increment Operator • Decrement Operator • Boolean Data Type • Relational Operators

Contents • Increment Operator • Decrement Operator • Boolean Data Type • Relational Operators • Equality Operators • Conditional Operators • Selectional Constructs 03 August 2004 [email protected] iitb

Increment Operators • i + + first use the value of i and then

Increment Operators • i + + first use the value of i and then increment it by 1. ‘i + +’ equivalent to ‘i = (i)+1’. // postfix increment • + + i first increment the value of i by 1 and then use it. ‘+ + i’ equivalent to ‘i = (i+1)’. // prefix increment i=2; • System. out. print(“ i = ”+ i++); //print 2, then i becomes 3 • System. out. print(“ i = ”+ ++i); //add 1 to i, then print 4 • Refer to incre. java 03 August 2004 [email protected] iitb

Decrement Operators • i - - first use the i ’s value and then

Decrement Operators • i - - first use the i ’s value and then decrement it by one i - - equivalent to (i)-1. // postfix decrement • - - i first decrement i ’s value by one and then use it. - - i equivalent to (i-1). // prefix decrement i=5; System. out. print(“i = ” + i--); //print 5, then i becomes 4 System. out. print(“i = ” + --i); //subtract 1 from i, then print 3 Refer to decre. java 03 August 2004 [email protected] iitb

Boolean Data Type This data type can store only two values; true and false.

Boolean Data Type This data type can store only two values; true and false. Declaring a boolean variable is the same as declaring any other primitive data type like int, float, char. boolean response = false; //Valid answer = true; //Valid answer = 9943; //Invalid, response = “false”; // Invalid, This is return type for relational & conditional operators. Refer to bool_op. java 03 August 2004 [email protected] iitb

Relational Operators a < b a less than b. (true/false) a <= b a

Relational Operators a < b a less than b. (true/false) a <= b a less than or equal b. (true/false) a > b a greater than b. (true/false) a >= b a greater than or equal to b. (true/false) These operations always return a boolean value. System. out. println(“ 23 is less than 65 ” +23<65); // true System. out. println(“ 5 is greater than or equal to 25. 00? ” + 5>=25. 00); // false Refer to relate. java 03 August 2004 [email protected] iitb

Equality Operators a==b a equal to b. (true/false) a!=b a not equal to b.

Equality Operators a==b a equal to b. (true/false) a!=b a not equal to b. (true/false) boolean equal = 12 = = 150; // false boolean again_equal = ‘r’= = ‘r’); // true boolean not_equal = 53!=90); // true Refer: equa. java 03 August 2004 [email protected] iitb

Conditional Operators • A conditional operator is used to handle only two boolean expressions.

Conditional Operators • A conditional operator is used to handle only two boolean expressions. Boolean expression always returns ‘true’ or ‘false’. • Conditional AND ‘&&’ Return value is ‘true’ if both, x and y are true, else it is ‘false’. System. out. println(“x&&y ” + x&&y); // Refer cond_and. java • Conditional OR ‘||’ return value is true if any one of x or y, is true else it is false. System. out. println(“x||y ” + x||y); // Refer cond_or. java 03 August 2004 [email protected] iitb

The ‘ if ’ construct It is used to select a certain set of

The ‘ if ’ construct It is used to select a certain set of instructions. It is used to decide whether this set is to be carried out, based on the condition in the parenthesis. Its syntax is: if (<boolean expression>){ //body starts <statement(s)> //body ends } The <boolean expression> is evaluated first. If its value is true, then the statement(s) are executed. And then the rest of the program. Refer if_cond. java, if_cond 1. java 03 August 2004 [email protected] iitb

The ‘if else’ construct It is used to provide an alternative when the expression

The ‘if else’ construct It is used to provide an alternative when the expression in if is false. Its syntax is: if(<boolean expression>){ <statement(s)> } else{ <statement(s)> } The if construct is the same. But when the expression inside if is false then else part is executed. Refer ifelse_cond. java 03 August 2004 [email protected] iitb

Assignments int a_number=1; // (range: 1 to 5 including both) Print the value of

Assignments int a_number=1; // (range: 1 to 5 including both) Print the value of a_number in word. For example, it should print “Four” if a_number contains 4. 1. 2. Use equality ‘= =’ operator. Do not use equality ‘= =’ operator. 03 August 2004 [email protected] iitb

End Thank You! 03 August 2004 nlp-ai@cse. iitb

End Thank You! 03 August 2004 [email protected] iitb