Output and Basic Data Types

# Output and Basic Data Types --- ## Agenda - Revise Initial Rules - Evaluating Expression - Quizzes - Concatenation - Intro to variable --- # Section 2.1 (Revision) 1. end statements with a **semicolon ( ; )** 2. JAVA is **case sensitive.** -> System, system are considered different 3. In order to print text, we use **double quotes ( " " )** 4. {}, (), " " --> All of these are in pairs. 5. Comments → * **Single-line comments** start with two forward slashes ( // ). Any text between // and the end of the line is ignored by Java (will not be executed). * **Multi-line comments** start with /* and ends with \*/. Any text between /* and */ will be ignored by Java. 6. **System.out.print(); →** Just type the output 7. **System.out.println(); →** Just type the output and press Enter [cursor moves to the next line] Now, let's check how much they remember from the last class with the help of quizzes. --- # Question What will be output for this ? ``` System.out.print("Welcome in playground") ``` # Choices - [ ] Welcome Home - [ ] Welcome in playground - [x] Error - [ ] All the options are correct --- # Question What will be output for this ? ``` system.out.print("Hi Everyone"); ``` # Choices - [ ] Hi Everyone - [ ] Bye Everyone - [x] Error - [ ] Welcome Everyone --- # Question What will be output for this ? ``` System.ouT.print("Hi Guys"); ``` # Choices - [ ] Hi Guys - [ ] Bye Guys - [x] Error - [ ] Welcome Guys --- # Question What will be output for this ? ``` System.out.print(Good Morning Everyone); ``` # Choices - [ ] Good Morning Everyone - [ ] Good Afternoon Everyone - [x] Error - [ ] Good Night Everyone --- # Question What will be output for this ? ``` System.out.print('Happy Thursday'); ``` # Choices - [ ] Happy Thursday - [ ] Sad Thursday - [x] Error - [ ] All the options are correct --- # Question What will be output for this ? ``` System.out.print(10 + 20); ``` # Choices - [x] 30 - [ ] 10+20 - [ ] Error --- # Question What will be output for this ? ``` System.out.print(10 - 25); ``` # Choices - [x] -15 - [ ] 15 - [ ] 10 - [ ] Error --- # Question What will be output for this ? ``` System.out.println("Hello"); System.out.print("World); ``` # Choices - [ ] Hello World - [ ] HelloWorld - [x] Error - [ ] inky pinky po --- # Question What will be output for this ? ``` System.out.print("Hello"); System.out.println("World"); ``` # Choices - [ ] Hello World - [x] HelloWorld - [ ] Error - [ ] inky pinky po --- # Question What will be output for this ? ``` System.out.println("Hello"); System.out.print("World"); System.out.println("Welcome") ``` # Choices - [ ] Hello World Welcome - [ ] HelloWorldWelcome - [x] Error - [ ] Hello WorldWelcome --- # Question What will be output for this ? ``` System.out.printLN("Hello"); System.out.println("World); ``` # Choices - [ ] Hello World - [ ] HelloWorld - [x] Error - [ ] inky-pinky-po --- # Question What will be output for this ? ``` Which of the follwing are operators? ``` # Choices - [ ] ( + ) - [ ] ( - ) - [ ] ( * ) - [ ] ( / ) - [x] All of them --- # Question ``` 10+30 In the given expression choose the operands. ``` # Choices - [ ] (+) - [ ] 10 - [ ] 30 - [x] Both 10 and 30 --- **Explanation of Quiz :** Operator : + Operands : 10 and 30 Explain using one more example if needed. Numbers -> 2 types 1. Decimal -> Numbers that have Decimal point Ex. 4.67, 0.986, 20.73, 2.0 2. Non Decimal / Integer -> Any +ve, -ve or 0 Ex. 7, -30, 0, -7 - Note: In today's class, we will only discuss Integers. Very Basic expression on simple maths. Time of the quiz is 20sec. --- # Question What will be output for this ? ``` System.out.print(5 + 8); ``` # Choices - [ ] 11 - [ ] 12 - [x] 13 - [ ] 14 --- # Question What will be output for this ? ``` System.out.print(5 - 8); ``` # Choices - [ ] -1 - [ ] -2 - [x] -3 - [ ] -4 --- # Question What will be output for this ? ``` System.out.print(5 * 8); ``` # Choices - [ ] 30 - [ ] 32 - [x] 40 - [ ] 42 --- # Question What will be output for this ? ``` System.out.print(8 / 2); ``` # Choices - [ ] 3 - [x] 4 - [ ] 5 - [ ] 6 --- # Question What will be output for this ? ``` System.out.print(10 / 3); ``` # Choices - [ ] 3.3333 - [x] 3 - [ ] Error - [ ] None of them --- **Explanation :** In calculator, 10 / 3 = 3.33333 But in JAVA, we get 3 **Rule :** In JAVA, when you divide (/) integers we only get quotient. --- # Question What will be output for this ? ``` System.out.print(24 / 9); ``` # Choices - [ ] 1 - [ ] 2.54 - [x] 2 - [ ] 3 --- # Question What will be output for this ? ``` System.out.print(3 / 6); ``` # Choices - [ ] 1 - [x] 0 - [ ] Error --- # Question What will be output for this ? ``` System.out.print(24 / 0); ``` # Choices - [ ] Infinite - [ ] 24 - [ ] 0 - [x] Error --- ## **Rule:** Division of integers by zero is not possible in JAVA --- # Question What will be output for this ? ``` System.out.print(6 * 7 / 6); ``` # Choices - [x] 7 - [ ] 6 - [ ] None of them - [ ] All of them --- **Explanation:** <img src= "https://d2beiqkhq929f0.cloudfront.net/public_assets/assets/000/050/233/original/upload_62530fdedbeb3e0a6c288afc122c7b4b.png?1695416761" alt = "" width ="700" height = "350"> But we cannot have two answers for the same expression. So, there must be some rules in place to get the output. --- ## Priority in Operators: 1. Rank 1 : **()** 2. Rank 2 : __*__ , __/__ 3. Rank 3 : __+__ , __-__ ### Few important rules of doing operations * **Rule 1 :** If we have same priority operators, whichever comes first from left to right that will be evaluated first. * **Rule 2 :** If we have different priority operators, whichever has highest priority that will be evaluated first. **Explanation:** Here, * and / have same priority. Because * comes first we will evaluate 6 * 7 will be evaluated first. => 6 * 7 / 6 => 42 / 6 => 7 --- # Question What will be output for this ? ``` System.out.print(4 + 3 * 6 - 7 / 2); ``` # Choices - [ ] 16 - [ ] 17 - [ ] 18 - [x] 19 --- **Explanation:** Between * and / we will be evaluating multiply first and then divide. => 4 + 3 * 6 - 7 / 2 => 4 + 18 - 7 / 2 => 4 + 18 - 3 => 22 - 3 => 19 --- # Question What will be output for this ? ``` System.out.print(5 + 2 * 3); ``` # Choices - [ ] 21 - [ ] 17 - [x] 11 - [ ] Error --- **Explanation:** Here, * has higher priority. => 5 + 2 * 3 => 5 + 6 => 11 --- # Question What will be output for this ? ``` System.out.print(5 + 15 / 5 + 6 * 3); ``` # Choices - [ ] 30 - [x] 26 - [ ] 11 - [ ] Error --- **Explanation:** => 5 + 15 / 5 + 6 * 3 => 5 + 3 + 6 * 3 => 5 + 3 + 18 => 8 + 18 => 26 --- # Question What will be output for this ? ``` System.out.print(7 - 2 * 4 + 18 / 3); ``` # Choices - [ ] 15 - [x] 5 - [ ] 30 - [ ] Error --- **Explanation:** => 7 - 2 * 4 + 18 / 3 => 7 - 8 + 18 / 3 => 7 - 8 + 6 => -1 + 6 => 5 --- # Question What will be output for this ? ``` System.out.print(3 * 4 / 2 + 7 + 3 - 4 / 2); ``` # Choices - [ ] 21 - [x] 14 - [ ] 11 - [ ] Error --- **Explanation:** => 3 * 4 / 2 + 7 + 3 - 4 / 2 => 12 / 2 + 7 + 3 - 4 / 2 => 6 + 7 + 3 - 4 / 2 => 6 + 7 + 3 - 2 => 13 + 3 - 2 => 16 - 2 => 14 --- # Question What will be output for this ? ``` System.out.print(5 + 2 * 4 + 8 - 6 + 12 / 4); ``` # Choices - [ ] 25 - [x] 18 - [ ] 16 - [ ] Error --- **Explanation:** => 5 + 2 * 4 + 8 - 6 + 12 / 4 => 5 + 8 + 8 - 6 + 12 / 4 => 5 + 8 + 8 - 6 + 3 => 13 + 8 - 6 + 3 => 21 - 6 + 3 => 15 + 3 => 18 --- # Question What will be output for this ? ``` System.out.print( (5 + 2) * 3 ); ``` # Choices - [x] 21 - [ ] 17 - [ ] 11 - [ ] Error --- **Explanation:** => (5 + 2) * 3) => 7 * 3 => 21 --- # Question What will be output for this ? ```java System.out.print("Hello" + "World"); ``` # Choices - [ ] Hello World - [x] HelloWorld - [ ] Error - [ ] I'm sleeping, Don't Disturb --- **Explanation:** <img src = "https://d2beiqkhq929f0.cloudfront.net/public_assets/assets/000/050/234/original/upload_9d8f2e7e5fa8e1f3b5bdd0b1c4c521c9.png?1695417058" width = "700" height = "450"> **Rule:** With + operator, If one Operand is text then we concatenate both Operands --- # Question What will be output for this ? ``` System.out.print("Hi" + "Students" + "Namaste"); ``` # Choices - [x] HiStudentsNamaste - [ ] HelloEveryone - [ ] Error - [ ] I'm Angry :( --- **Explanation:** => "Hi" + "Students" + "Namaste" => "HiStudents" + "Namaste" => "HiStudentsNamaste" --- # Question What will be output for this ? ``` System.out.print("Hi" + " " + "Namaste"); ``` # Choices - [x] Hi Namaste - [ ] HiNamaste - [ ] Error - [ ] Namaste Hi --- **Explanation:** => "Hi" + " " + "Namaste" => "Hi " + "Namaste" => "Hi Namaste" --- # Question What will be output for this ? ``` System.out.print("Hi" * "Guys"); ``` # Choices - [ ] HiGuys HiGuys HiGuys - [x] Error - [ ] abcdefghijklmnopqrstuvwxyz - [ ] Hi Guys --- **Explanation:** We cannot use * with text operand. ## **Rule:** With text operand, only + operator can be used. Any other operator gives error. --- # Question What will be output for this ? ``` System.out.print("WelcomeHome" - "Home"); ``` # Choices - [ ] Welcome - [ ] WelcomeHome-Home - [ ] Home - [x] Error --- **Explanation:** We cannot use - with text operand. --- # Question What will be output for this ? ``` System.out.print("Hello" + 3); ``` # Choices - [ ] Hello - [x] Hello3 - [ ] Error - [ ] HelloHelloHello --- **Explanation:** Operator: + Operands: "Hello" -> text 3 -> number Since, one operand is text, we concatenate both operands. --- # Question What will be output for this ? ``` System.out.print("Hello" + 3 + 4); ``` # Choices - [ ] Hello - [x] Hello34 - [ ] Hello7 - [ ] Error --- **Explanation:** Since, both operators are + and have same priority we will evaluate from left to right => "Hello" + 3 + 4 => "Hello3" + 4 => "Hello34" --- # Question What will be output for this ? ``` System.out.print("Hello" + 10 + "World"); ``` # Choices - [ ] HelloWorld - [x] Hello10World - [ ] Hello10 - [ ] Error --- **Explanation:** => "Hello" + 10 + "World" => "Hello10" + "World" => "Hello10World" --- # Question What will be output for this ? ``` System.out.print(10 + "Welcome"); ``` # Choices - [ ] Welcome10 - [x] 10Welcome - [ ] Welcome 10 times - [ ] inky pinky po --- **Explanation:** => 10 + "Welcome" => "10Welcome" --- # Question What will be output for this ? ``` System.out.print(10 + 20 + "WakeUp" + 3 + 2); ``` # Choices - [ ] 1020WakeUp32 - [ ] 1020WakeUp5 - [ ] 30WakeUp5 - [x] 30WakeUp32 --- **Explanation:** => 10 + 20 + "WakeUp" + 3 + 2 => 30 + "WakeUp" + 3 + 2 => "30WakeUp" + 3 + 2 => "30WakeUp3" + 2 => "30WakeUp32" --- # Question What will be output for this ? ``` System.out.print("HiGuys" * 2); ``` # Choices - [ ] HiGuys*2 - [ ] HiGuys2 - [ ] HiGuysHiGuys - [x] Error --- **Explanation:** We cannot use * operator with text operand --- # Question What will be output for this ? ``` System.out.print(10 + 20 + "WakeUp" + 3 * 2); ``` # Choices - [ ] 1020WakeUp32 - [ ] 30WakeUp32 - [ ] Error - [x] 30WakeUp6 --- **Explanation:** => 10 + 20 + "WakeUp" + 3 * 2 => 10 + 20 + "WakeUp" + 6 => 30 + "WakeUp" + 6 => "30WakeUp" + 6 => "30WakeUp6" --- # Question What will be output for this ? ``` System.out.print(10 + "Hello" * "World" + 3); ``` # Choices - [ ] 10HelloWorld3 - [ ] 10HelloWorldWorldWorld3 - [x] Error - [ ] Good Morning :) --- **Explanation:** We cannot use * operator with text operand --- # Question What will be output for this ? ``` System.out.print(10 + "WelcomeHome" - "Home" + 3); ``` # Choices - [ ] 10Welcome3 - [ ] 10WelcomeHomeHome3 - [x] Error - [ ] Good Morning :) --- **Explanation:** We cannot use - operator with text operand --- # Question Predict the output for the following code: ``` System.out.println(10 + 20 + "Hello"); ``` # Choices - [ ] 1020Hello - [x] 30Hello - [ ] Hello1020 - [ ] Hello Hello Hello --- **Explanation** 10 + 20 = 30, Now when string is concatenated then 30 becomes as string "30" so the answer is "30Hello". --- # Section 2.3 (Introduction to Variables) > Start with that numbers are of two types: 1. **Non-Decimal / Integers** 2. Decimals **Story :** Assume we have a container storing water in it. And then explain the three factors of container that are : Type, Name and Value After that take a container to store integers and explain the same three factors. <img src = "https://d2beiqkhq929f0.cloudfront.net/public_assets/assets/000/050/235/original/upload_23ef2438b9c3b2043ca7f53fffb61f9d.png?1695417557" width = "750" height = "350"> In programming, containers are known as variables. ## Creating a variable: <img src = "https://d2beiqkhq929f0.cloudfront.net/public_assets/assets/000/050/236/original/upload_4734a0a6fd149a8b7767b1498637f82a.png?1695417585" width = "750" height = "250"> --- # Question What will be output for this ? ```java Create a variable of type int and give name as num and assign 34 in it. ``` # Choices - [ ] num = 34 - [x] int num = 34; - [ ] int 34 num - [ ] num int = 34 --- # Question What will be output for this ? ``` int val = 30; System.out.println(val); ``` # Choices - [ ] val - [x] 30 - [ ] Error - [ ] Don't Select me, I'm wrong option --- **Explanation:** The value of variable val is 30. **Rule :** Whenever we use variable name, the value of that variable is used. --- # Question What will be output for this ? ``` int a = 10; int b = 20; System.out.println(a + b); ``` # Choices - [ ] ab - [x] 30 - [ ] Error - [ ] Keep focus on the above option, I am wrong --- # Question What will be output for this ? ``` int a = 10; int b = 20; System.out.println("Sum of Number is " + a + b); ``` # Choices - [ ] Sum of Number is 30 - [x] Sum of Number is 1020 - [ ] Error - [ ] Above Options, Not me :) --- **Explanation:** Here, both operators are + and have same priority. Hence, the exppression will be evaluated from left to right. => "Sum of Number is " + a + b => "Sum of Number is " + 10 + 20 => "Sum of Number is 10" + 20 => "Sum of Number is 1020" --- # Question What will be output for this ? ``` int a = 10; int b = 20; System.out.println("Product of Number is " + a * b); ``` # Choices - [ ] Product of Number is 1020 - [x] Product of Number is 200 - [ ] Error - [ ] Again Above Options, Not me :) --- **Explanation:** Here, * has highest priority. So, a * b will be evaluated first. => "Product of Number is " + a * b => "Product of Number is " + 10 * 20 => "Product of Number is " + 200 => "Product of Number is 200" --- # Section 2.4 (Summary) 1. In Java, when we divide ( / ) integers we only get quotient. 2. We cannot divide integers by 0, we get error. 3. Priority of Operators : * Rank 1 : **()** * Rank 2 : __*__ , __/__ * Rank 3 : __+__ , __-__ 4. When two operators of different priority are there, we evaluate the one with higher priority first. 5. When two operators of same priority are there, we evaluate the one which comes first from left to right. 6. With + operator, if one of the operand is text then we concatenate both the operands. 7. Creating a variable: * type name = value; * Way 1 : * int x = 30; * Way 2 : * int y; y = 40; 8. When we use variable name, we use its value.