Print Day of Week in Java
beginner· Control Flow · Switch Statement
Problem
Mapping a small fixed set of numbers to names, like 1 through 7 to weekday names, is exactly the kind of direct lookup a switch statement is built for.
Given a number from 1 to 7, print the matching day of the week.
Input
day = 3
Output
Wednesday
Java Program
Java
public class DayOfWeek {
public static void main(String[] args) {
int day = 3;
String dayName;
switch (day) {
case 1:
dayName = "Monday";
break;
case 2:
dayName = "Tuesday";
break;
case 3:
dayName = "Wednesday";
break;
case 4:
dayName = "Thursday";
break;
case 5:
dayName = "Friday";
break;
case 6:
dayName = "Saturday";
break;
case 7:
dayName = "Sunday";
break;
default:
dayName = "Invalid day"; // required so dayName is always assigned
}
System.out.println(dayName);
}
}Output
Wednesday
Core Logic
Matching the day number against each case label directly maps it to the corresponding day name.
How It Works
- 1
switch (day)compares the int against case labels1through7. - 2Each case assigns the matching day name to
dayNameandbreaks. - 3The
defaultcase catches any number outside 1-7 and assigns"Invalid day".
For
day = 3, the third case matches and assigns "Wednesday".💡
Key Point: The default case matters here specifically because the input is an arbitrary int — without it, a value like 0 or 8 would leave dayName unassigned and fail to compile.
Key Concepts
switch statementint case labelsdefault case