- \n
- if<\/li>\n
- if-else<\/li>\n
- nested-if<\/li>\n
- if-else-if<\/li>\n
- switch-case<\/li>\n
- jump-break, continue, return<\/li>\n<\/ul>\n
If Statement in Java<\/h3>\n
Java if statement is the simplest decision-making statement. It encompasses a boolean condition followed by a scope of code, which is executed only when the condition evaluates to true. However, if there are no curly braces to limit the scope of sentences to be executed if the condition evaluates to true, then only the first line is executed.<\/p>\n
Syntax of the if statement in Java:<\/strong><\/p>\n
if(condition)
\n{
\n\/\/code to be executed
\n}<\/p>\nFlow diagram for Java if statement:<\/strong><\/p>\n
![\"If](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/01\/Flow-diagram-for-if-statement.jpg\")
<\/a><\/p>\nExample Java program to understand if statement:<\/strong><\/p>\n
package com.dataflair.decisionmaking;\r\npublic class IfStatement {\r\n public static void main(String[] args) {\r\n\r\n System.out.println(\"Understanding if statements.\");\r\n String s = \"DataFlair\";\r\n if (s.equals(\"DataFlair\")) {\r\n System.out.println(\"The string is DataFlair\");\r\n }\r\n }\r\n}<\/pre>\nOutput<\/strong><\/p>\n
Understanding if statements.
\nThe string is DataFlair<\/div>\nif-else statement in Java<\/h3>\n
This pair of keywords is used to divide a program to be executed into two parts, one being the code to be executed if the condition evaluates to true, and the other being executed if the value is false.<\/p>\n
However, if no curly braces are given, the first statement after the if or else keyword is executed.<\/p>\n
if(condition)
\n{
\n\/\/code to be executed if the condition is true
\n}
\nelse
\n{
\n\/\/code to be executed if the condition is false
\n}<\/p>\nFlow Diagram of Java if-else statement:<\/strong><\/p>\n
![\"if](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/01\/Flow-diagram-of-if-else-statement.jpg\")
<\/a><\/p>\nJava program to illustrate the use of the if-else statement:<\/strong><\/p>\n
package com.dataflair.decsionmaking;\r\npublic class IfElseStatement {\r\n public static void main(String[] args) {\r\n\r\n System.out.println(\"Understanding if statements.\");\r\n String s = \"DataFlairJava\";\r\n if (s.equals(\"DataFlair\")) {\r\n System.out.println(\"The string is DataFlair\");\r\n }\r\n else {\r\n System.out.println(\"The string is not DataFlair\");\r\n }\r\n }\r\n}<\/pre>\nOutput<\/strong><\/p>\n
The string is not DataFlair<\/div>\nNested if Statements in Java<\/h3>\n
The nested if is similar to the nested loops we learned about in the previous chapters.<\/p>\n
The nested if statements are those that have further if-else statements inside them. The outer if statement is considered the entry checkpoint, which means that if the condition in the outer if statement is true, then only the inner if-else block gets executed. A program can have multiple if-else blocks inside an if statement. Look at the flow diagram of the program to get it clear.<\/p>\n
Syntax of nested if statements in Java:<\/strong><\/p>\n
if(condition)
\n{
\n\/\/code to be executed
\nif(condition)
\n{
\n\/\/code to be executed
\n}
\n}<\/p>\nFlow diagram of Java nested if statement:<\/strong><\/p>\n
![\"nested](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/01\/Flow-diagram-a-nested-if-statement.jpg\")
<\/a><\/p>\nJava program to illustrate the use of nested if:<\/strong><\/p>\n
package com.dataflair.decisionmaking;\r\npublic class IfNestedStatement {\r\n public static void main(String[] args) {\r\n\r\n System.out.println(\"Understanding if statements.\");\r\n String s = \"DataFlair\";\r\n if (s.equals(\"DataFlair\")) {\r\n System.out.println(\"The string is DataFlair\");\r\n if (s.charAt(0) == 'D') {\r\n System.out.println(\"The first character is D! \");\r\n }\r\n }\r\n else {\r\n System.out.println(\"The string is not DataFlair\");\r\n }\r\n }\r\n}<\/pre>\nOutput<\/strong><\/p>\n
Understanding if statements.
\nThe string is DataFlair
\nThe first character is D!<\/div>\nif-else-if Statements in Java<\/h3>\n
These statements are similar to the if-else statements. The only difference lies in the fact that each of the else statements can be paired with a different if condition statement. This renders the ladder as a multiple-choice option for the user. As soon as one of the if conditions evaluates to true, the equivalent code is executed, and the rest of the ladder is ignored.<\/p>\n
Syntax of if-else-if statements in Java:<\/strong><\/p>\n
if
\n{
\n\/\/code to be executed
\n}
\nelse if(condition)
\n{
\n\/\/code to be executed
\n}
\nelse if(condition)
\n{
\n\/\/code to be executed
\n}
\nelse
\n{
\n\/\/code to be executed
\n}<\/p>\nFlow Diagram of Java if-else-if statements:<\/strong><\/p>\n
![\"if](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/01\/Flow-Diagram-of-if-else-if-statements.jpg\")
<\/a><\/p>\nJava program to illustrate the use of if-else-if statements:<\/strong><\/p>\n
package com.dataflair.decisionmaking;\r\npublic class IfElseIfStatement {\r\n public static void main(String[] args) {\r\n\r\n System.out.println(\"Understanding if statements.\");\r\n String s = \"DataFlairPython\";\r\n if (s.equals(\"DataFlair\")) {\r\n System.out.println(\"The string is DataFlair\");\r\n }\r\n else if (s.equals(\"DataFlairJava\")) {\r\n System.out.println(\"The string is DataFlair and course is Java\");\r\n }\r\n else if (s.equals(\"DataFlairPython\")) {\r\n System.out.println(\"The string is DataFlair and the course is Python\");\r\n }\r\n }\r\n}<\/pre>\nOutput<\/strong><\/p>\n
Understanding if statements.
\nThe string is DataFlair and the course is Python<\/div>\nSwitch Statement in Java<\/h3>\n
The Java switch statement is a different form of the if-else-if ladder statements.<\/p>\n
- \n
- This saves the hassle of writing else if for every different option.<\/li>\n
- It branches the flow of the program to multiple points as and when required or specified by the conditions.<\/li>\n
- It bases the flow of the program based on the output of the expression.<\/li>\n
- As soon as the expression is evaluated, the result is matched with every case listed in the scope. If the output matches any of the cases mentioned, then the particular block is executed. A break statement is written after every end of the case block so that the remaining statements are not executed.<\/li>\n
- The default case is written, which is executed if none of the cases is the result of the expression. This is generally the block where error statements are written.<\/li>\n<\/ul>\n
Syntax of switch statement in Java:<\/strong><\/p>\n
switch(expression)
\n{
\ncase <value1>:
\n\/\/code to be executed
\nbreak;
\ncase <value2>:
\n\/\/code to be executed
\nbreak;
\ndefault:
\n\/\/code to be defaultly executed
\n}<\/p>\nFlow Diagram of Java switch statement:<\/strong><\/p>\n
![\"switch](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/01\/Flow-Diagram-of-the-switch-statement.jpg\")
<\/a><\/p>\nJava program to illustrate the switch statement:<\/strong><\/p>\n
package com.dataflair.decisionmaking;\r\nimport java.util. * ;\r\npublic class SwitchStatement {\r\n public static void main(String[] args) {\r\n Scanner sc = new Scanner(System. in );\r\n System.out.println(\"You have two options of courses at DataFlair\");\r\n System.out.println(\"1.Java\");\r\n System.out.println(\"2.Python\");\r\n System.out.println(\"Enter the number of course:\");\r\n int ch = sc.nextInt();\r\n switch (ch) {\r\n case 1:\r\n System.out.println(\"Congrats you have chosen Java!\");\r\n break;\r\n case 2:\r\n System.out.println(\"Congrats you have chosen Python!\");\r\n break;\r\n default:\r\n System.out.println(\"Wrong input!\");\r\n break;\r\n }\r\n\r\n }\r\n}<\/pre>\nOutput<\/strong><\/p>\n
You have two options of courses at DataFlair
\n1.Java
\n2.Python
\nEnter the number of course:
\n2
\nCongrats you have chosen Python!<\/div>\nJump Statements in Java<\/h3>\n
The Java jump statements are the keywords in Java which have a specific meaning and a specific action of disrupting the normal flow of the program. Some of them are:<\/p>\n
1. Java break statement<\/h4>\n
The break statement in Java, as the name signifies, is useful to break out of the normal workflow of a program. We can use it to terminate loops, end cases of switch statements, and as a goto statement. Break statements, if used in a nested loop, terminate the innermost loop. The outermost loop still functions.<\/p>\n
break statement as a goto statement in Java<\/strong><\/p>\n
If we mention a label after the break keyword, the control shifts to the end of the particular label scope. Java prohibits the use of goto statements because it encourages branched behaviour of programming. However, break labels function like goto statements.<\/p>\n