if Statement
if(condition) if_true_statement; //if condition is true this statement will be executed else if_false statement; //if condition is false this statement will be executed
if(condition) if_true_statement; //if condition is true this statement will be executed else if(condition) if_true statement; //if condition is true this statement will be executed .... else if_false statement; //if condition is false this statement will be executed
if more than one statement is to be executed after the evaluation of the condition then those statements are enclosed within the curly brackets. It is not necessary to write else part in every if statement, it depends on the situation.
if(age >=18) System.out.println("You can ride a bike"); else System.out.println("You have to wait for few more years to ride a bike.");
if(text.equals("search") && isPrime(number)){ System.out.println("Search records with id as prime number"); }
if(day.equals("Sunday")){ System.out.println("\n1.Chatamari\n2.Momo\n3.Bara\n4.Masu Chura\n5.Samosa\n6.Pizza.\n7.Burger"); }else if(day.equals("Monday")){ System.out.println("\n1.Chatamari\n2.Momo\n3.Bara\n4.Allu Tama\n5.Samosa\n6.Chowmin.\n7.Hot Dogs"); }else if(day.equals("Tuesday")){ System.out.println("\n1.Fry Rice\n2.Momo\n3.Fried Prawn\n4.Fish curry\n5.Sandwich\n6.Pizza.\n7.Burger"); }else{ System.out.println("Have to take order"); }
In the given program two integers are defined x and y; x is assigned 444 and y is not assigned any value, by default it will be zero. if statement is used to check if the value of x is less than 1000, if less than 1000, message is displayed.
Then Object of class Scanner is created, method nextInt() is used to take integer from user. Two integers are taken from user, one at a time, and assigned to x and y respectively. Then if value of x is greater than y is checked; Output is given.
import java.util.Scanner; class if_demo{ public static void main(String[] ops){ int x = 444, y; if(x < 1000) System.out.println("Value of x is less than 1000"); Scanner sc = new Scanner(System.in); System.out.print("Enter a number: "); x = sc.nextInt(); System.out.print("Enter a number: "); y = sc.nextInt(); if(x > y){ System.out.println(x+" is greater than "+y); }else{ System.out.println(x+" is less than "+y); } } } Output: 33 44 33 is less than 44
Following program asks user to provide a line of words. Object of class Scanner is created; method nextLine() of Scanner object is used to take a line from the user. Then if statement is used to check if the length of the provided line lies between 3 and 10 or not.
import java.util.Scanner; class if_demo{ public static void main(String[] app){ String str; Scanner sc = new Scanner(System.in); System.out.println("Enter a word: "); str = sc.nextLine(); if(str.length()>=3 && str.length() <=10){ System.out.println("Length of "+str +" lies between 3 and 10"); }else{ System.out.println(str +" is either shorter than 3 characters or greater than 10."); } } } Output: Enter a word: Fish Tail Length of Fish Tail lies between 3 and 10 Kanchanjunga Kanchanjunga is either shorter than 3 characters or greater than 10.
In the given program three integers are taken from the user, Object of Scanner class is created, this class has several methods defined for taking different types of values from the keyboard; nextInt() method is used to take integer from user. Three number are taken as inputs; those three numbers are added and stored in variable sum. Then if statement is used to check if the sum lies between 270 and 300 or not. Second if statement is used to check if the sum lies between 210 and 270 or not. If both of the if statements evaluate to false then statement in the else part is executed.
import java.util.Scanner; class if_demo{ public static void main(String[] app){ int a, b, c, sum; Scanner sc = new Scanner(System.in); System.out.print("Enter a number: "); a = sc.nextInt(); System.out.print("Enter a number: "); b = sc.nextInt(); System.out.print("Enter a number: "); c = sc.nextInt(); sum = a + b + c; if(sum >=270 && sum <= 300) System.out.println("You got very good total of "+sum); else if(sum >=210 && sum < 270) System.out.println("You got fair total of "+sum); else System.out.println("You got low total of "+sum); } } Output: First run: Enter a number: 88 Enter a number: 100 Enter a number: 99 You got very good total of 287 Second run: Enter a number: 90 Enter a number: 60 Enter a number: 70 You got fair total of 220 Third run: Enter a number: 80 Enter a number: 40 Enter a number: 40 You got low total of 160
Two words are taken from the user; those words are compared using compareTo() method of the string object. This method compareTo() takes a string as parameter and is called by a string; strings are equal if the value returned is 0, first string is greater than second string if value returned by compareTo method is greater than 0; first string is less than second string if the value returned by compareTo method is less than 0. Strings are compared based on the alphabetical order. Output of the program is given.
import java.util.Scanner; class if_demo{ public static void main(String[] app){ String word1,word2; Scanner sc = new Scanner(System.in); System.out.print("Enter a word: "); word1 = sc.next(); System.out.print("Enter a word: "); word2 = sc.next(); if(word1.compareTo(word2) == 0){ System.out.println(word1+ " and "+word2 +" are equal."); } if(word1.compareTo(word2) > 0){ System.out.println(word1+ " is lexicographically greater than "+word2); } if(word1.compareTo(word2) < 0){ System.out.println(word1+ " is lexicographically less than "+word2); } } } Output: First run: Enter a word: lion Enter a word: tiger lion is lexicographically less than tiger Second Run: Enter a word: eagle Enter a word: eagle eagle and eagle are equal. Third Run: Enter a word: Parrot Enter a word: Crow Parrot is lexicographically greater than Crow
In the given program below user is asked to enter a text. Object of class Scanner is created; Scanner class has methods to take different type of data values from keyboard. Scanner class is defined in the java.util package. It is a build in class. if statement is used to check if the text input by user contains letter 'o' or not; next() method of the Scanner object is used to take text from the user. Then second input asks user to input another text (a line); nextLine() method of Scanner object is used to take input. Then if statement is used to see if the second input text contains first input text or not. Output of the program is given just below the program code.
import java.util.Scanner; class if_demo{ public static void main(String[] app){ String word1,word2; Scanner sc = new Scanner(System.in); System.out.print("Enter a text: "); word1 = sc.nextLine(); System.out.println("Checking if given text contains character o or not:"); if(word1.indexOf('k')>-1){ System.out.println("Given text "+word1+" contains o"); }else System.out.println("Given text "+word1+" does not contain o"); System.out.print("Enter a word: "); word2 = sc.next(); System.out.println("Checking if first entered word contains second entered word or not:"); if(word1.indexOf(word1)>-1){ System.out.println("Given word "+word1+" contains "+word2); }else System.out.println("Given word "+word1+" does not contain "+word2); } } Output: Enter a text: Mission Impossible Checking if given text contains character o or not: Given text Mission Impossible does not contain o Enter a word: possible Checking if first entered word contains second entered word or not: Given word Mission Impossible contains possible