The decision-making statement in Java is used when the user wants a specific block of code to be executed when the given condition is fulfilled.
Java programming language provides the following types of decision-making statements:
- if statement
- if-else statement
- nested-if statement
- if-else-if ladder statement
- switch-case statement
if statement
Among the decision making statements, it is the most simple one. It checks if the condition is true or not, and if it is true then it executes the block of code inside if otherwise, it will not. The block that is executed is placed within the curly braces({}).
Syntax of if statement in Java:
1 2 3 4 5 | if (boolean expression) { /* if expression is true */ statements... ; /* Execute statements */ } |
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if-else statement
There are two-part in this statement. First is the if statement, here it checks for the condition to be true and if it is true then it will execute the code present inside the if. But if the condition is false then the code inside the else statement will be executed.
Syntax of if-else statement in Java:
1 2 3 4 5 6 7 8 | if (condition) { //code executed if condition true } else { //code executed if condition false } |
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nested-if statement
This statement allows the user to use if block inside the other if block. And the inner if is executed only if the outer if is true in condition.
Syntax of nested if statement in java:
1 2 3 4 5 6 7 8 | if(condition1) { //block of code to be executed if(condition2) { //block of code to be executed } } |
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if-else-if ladder statement
This statement allows the user to have multiple options to check for different conditions. Here, if one of the if or else-if condition is true then that part of the code will be executed and the rest will be bypassed. if none of the conditions is true then the final else statement at the end will be executed.
Syntax of if-else-if ladder statement in java:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | if(condition1) { //code to be executed if condition1 is true } else if(condition2){ //code to be executed if condition2 is true } else if(condition3){ //code to be executed if condition3 is true } ... else{ //final else if all the above condition are false } |
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switch-case statement
A switch statement allows a variable to be tested for equality against multiple values. It provides the case for the different blocks of code to be executed. Switch expression and case value must be of the same type. There must be at least one case or multiple cases with unique case values.
In the end, it can have a default case which is optional that is executed if no cases are matched. It can also have an optional break that is useful to exit the switch otherwise it continues to the next case.
Syntax of switch statements in Java:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | { case value1: //code to be executed; break; //optional case value2: //code to be executed; break; //optional . . . . case valueN: //code to be executed; break; //optional default: code to be executed if all cases are not matched; } |
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