Decision-making statements decide which statement to execute and when. Decision-making statements evaluate the Boolean expression and control the program flow depending upon the result of the condition provided.
There are two types of decision-making statements in
Java,
If statement and switch statement.
1) If Statement:
The "if" statement is used to evaluate a
condition. The control of the program is diverted depending upon the specific
condition. The condition of the If statement gives a Boolean value, either true
or false.
In Java, there are four types of if-statements given
below.
- Simple if statement
- if-else statement
- if-else-if ladder
- Nested if-statement
1)
Simple if statement:
It is the most basic statement among all control
flow statements in Java. It evaluates a Boolean expression and enables the
program to enter a block of code if the expression evaluates to true.
Syntax:
if(condition) {
statement 1; //executes when condition is true
}
2)
if-else statement
The if-else statement is an extension to the
if-statement, which uses another block of code, i.e., else block. The else
block is executed if the condition of the if-block is evaluated as false.
Syntax:
if(condition) {
statement 1; //executes when condition is true
}
else{
statement 2; //executes when condition is false
}
3)
if-else-if ladder:
The if-else-if statement contains the if-statement
followed by multiple else-if statements.
In other words, we can say that it is the chain of
if-else statements that create a decision tree where the program may enter in
the block of code where the condition is true. An else statement can also be
defined at the end of the chain.
syntax:
if(condition 1) {
statement 1; //executes when condition 1 is true
}
else if(condition 2) {
statement 2; //executes when condition 2 is true
}
else {
statement 2; //executes when all the conditions are false
}
4.
Nested if-statement
In nested if-statements, the if statement can
contain a if or if-else statement inside
another if or else-if statement.
if(condition 1) {
statement 1; //executes when condition 1 is true
if(condition 2) {
statement 2; //executes when condition 2 is true
}
else{
statement 2; //executes when condition 2 is false
}
}
Switch
Statement:
Switch statements are similar to if-else-if statements. The switch
statement contains multiple blocks of code called cases and a single case is
executed based on the variable which is being switched. The switch statement is
easier to use instead of if-else-if statements. It also enhances the
readability of the program.
syntax:
switch (expression){
case value1:
statement1;
break;
.
.
.
case valueN:
statementN;
break;
default:
default statement;
}
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