Conditionals
Conditionals take an expression, which is code that evaluates to determine a value, and checks if it is true
or false
. If it’s true
, we can tell our program to do one thing — we can even account for false
to do another.
As we write more complex programs, conditionals allow us to address multiple scenarios and make our programs more robust.
If Statement
An if
statement executes a block of code when a specified boolean expression is evaluated as true
; otherwise, the block of code will be skipped.
if (berries > 5) {System.out.println("More than a handful of berries.");}
Else
An else
clause can be added to an if
statement.
The else
statement executes a block of code when the condition inside the if
statement is false
:
- If the condition evaluates to
true
, code in theif
part is executed. - If the condition evaluates to
false
, code in theelse
part is executed.
The else statement is always the last condition.
if (year == 2022) {System.out.println("Print if year is 2022");}else {System.out.println("Print if year is not 2022");}
Else If
else if
statements can be chained together to check multiple conditions. Once a condition is true
, a code block will be executed and the conditional statement will be exited.
There can be multiple else if
statements in a single conditional statement.
int testScore = 76;char grade;if (testScore >= 90) {grade = 'A';} else if (testScore >= 80) {grade = 'B';} else if (testScore >= 70) {grade = 'C';} else if (testScore >= 60) {grade = 'D';} else {grade = 'F';}System.out.println("Grade is " + grade);// Output: Grade is C
Nested Conditional Statements
A nested conditional statement is a conditional statement nested inside another conditional statement. The outer conditional statement is evaluated first; if the condition is true, then the nested conditional statement will be evaluated.
boolean studied = true;boolean wellRested = true;if (wellRested) {System.out.println("Best of luck today!");if (studied) {System.out.println("You are prepared for your exam!");} else {System.out.println("Study before your exam!");}}
The output would be:
Output: Best of luck today!Output: You are prepared for your exam!
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