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If Else : 2

Content

  • Revision Quizzes
  • Categorize triangle
  • Max of three
  • Fizz Buzz
  • Nested If Else
  • Categorize into positive, negative and zero

Success

There are a lot of quizzes in this session, please take some time to think about the solution on your own before reading further.....

Recap

Some abbreviations that will be used in this class:

  • System.out.print - SOP
  • System.out.println - SOPln

Question

What will be the output of the following code?

int a = 10,b = 10;
if(a >= 10 && b >= 10){
   System.out.print(a+b);
}

Choices

  • 10
  • 20
  • 30
  • None

Question

What will be the output of the following code?

int a = 10;
int b = 10;
if( ++ a >= 12 && ++ b >= 12 ){
  System.out.println("Hello");
}
System.out.println(a + b);

Choices

  • Hello
    10
  • 22
  • 21
  • None

Question

What will be the output of the following code?

int a = 10;
int b = 10;
if( ++ a >= 11 || ++ b >= 12 ){
  System.out.println("Hello");
}
System.out.println(a + b)

Choices

  • 20
  • 22
  • Hello
    21
  • None

Question

What will be the output of the following code?

int a = 10;
int b = 10;
if( ++ a >= 12 || ++ b >= 12 ){
  System.out.println("Hello");
}
System.out.println(a + b);

Choices

  • 20
  • 21
  • 22
  • None

Question

What will be the output of the following code?

int N = 5;
if(N > 2)
    System.out.println("Yayay");
else
    System.out.println("Blahblah!!");

Choices

  • Yayay
  • Blahblah!!

Question

What will be the output of the following code?

int N = 5;
if(N > 2)
    System.out.println("Yayay");
    System.out.println("Hmmmm");
else
    System.out.println("Blahblah!!");
    System.out.println("Blahblah!!");

Choices

  • Error :(
  • No Error, this code rocks! :D
  • Yayay Hmmmm
  • Blahblah!!

Question

What will be the output of the following code? 

int marks = 80; 
if(marks > 70) {
    System.out.print("Distinction "); 
    System.out.print("Congrats ");
} else if(marks > 35) { 
    System.out.print("Pass "); 
} else 
    System.out.print("Fail "); 
System.out.print("Good luck");

Choices

  • Distinction Congrats Good luck
  • Good luck
  • Error
  • Distinction Congrats

Categorize Triangles

Categorize triangle on the basis of the length of the sides

Equilateral: When the length of the all the sides are equal.

Isosceles: When the length of any two sides are equal.

Scalene: When the length of all sides are different.

Let a, b, c be the length of the three sides of a triangle. Given in each case they take some values, tell the category of the triangle. It is the given that the input values for a, b, c are positive integer values.

a = 20, b = 20, c = 20 
-- Output = Equilaterial

a = 7, b = 12, c = 9 
-- Output = Scalene

a = 5, b = 13, c = 5 
-- Output = Isosceles

a = 12, b = 7, c = 7 
-- Output = Isosceles

The equivalent code for implementing the above logic is as follows:

if(a == b && b == c){
   SOPln("Equilateral"); 
}
else if(a == b || b == c || a == c){
    SOPln("Isosceles");
}
else{
    SOPln("Scalene");
}

Max of three

Ques: Given three numbers, print the maximum among them.

“”

Note that a, b, c can take any integer values. Stress on the point that a, b, c can also take equal values. The three test case demonstrates this point.

For example,

  • a = 7, b = 20, c = 50 ==> max = 50
  • a = 10, b = 9, c = 10 ==> max = 10
  • a = 3, b = 3, c = 3 ==> max = 3

The equivalent code for implementing the above logic is as follows:

if(a >= b && a >= c){
   SOPln("a"); 
}
else if(b >= c){
    SOPln("b");
}
else{
    SOPln("c");
}

Fizz-Buzz

Ques: Given a number,

  • print "Fizz" if the number is divisible by 3.
  • print "Buzz" if the number is divisible by 5.
  • print "Fizz-Buzz" if the number is divisble by both 3 and 5.

For example,

  • n = 39, O/p = Fizz
  • n = 25, O/p = Buzz
  • n = 15, O/p = Fizz-Buzz
  • n = 13, O/p = No output

**How to implement this? **

The following code shows a wrong implementation of the above logic:

if(n % 3 == 0){
    SOPln("Fizz");
}
else if(n % 5 == 0){
    SOPln("Buzz");
}
else{
    SOPln("Fizz-Buzz");
}

The above code prints "Fizz-Buzz" for n = 11, but this is wrong as n is neither divisble by 3 nor 5. So there should have no output for this number.

Another wrong implementation is as follows:

if(n % 3 == 0){
    SOPln("Fizz");
}
else if(n % 5 == 0){
    SOPln("Buzz");
}
else if(n % 3 == 0 && n % 5 == 0){
    SOPln("Fizz-Buzz");
}

The above code prints "Fizz" for n = 15, but this is wrong as n is divisble by 3 and 5 both. So the correct output should be "Fizz-Buzz".

So finally, the correct implementation of this logic is as follows:

if(n % 3 == 0 && n % 5 == 0){
    SOPln("Fizz-Buzz");
}
else if(n % 3 == 0){
    SOPln("Fizz");
}
else if(n % 5 == 0){
    SOPln("Buzz");
}

Nested If Else

Syntax:

Statement 1
if(cond1){
    Statement 2
    if(cond2){
    Statement 3
    }
    else{
    Statement 4
    }
    Statement 5
}
else{
    Statement 6
    if(cond3){
    Statement 7
    }
    else{
    Statement 8
    }
    Statement 9
}
“”

Question

Predict the output of the following code?

int a = 10, b = 15;
if(a > 8) {
    if(a < b || b == 9) {
        System.out.println("Hi");
    }
    else {
        System.out.println("Bye");
    }
}
else {
    System.out.println("Good Bye");
}

Choices

  • Hi
  • Bye
  • Good Bye
  • None

Question

Predict the output of the following code?

int a = 10, b = 15;
if(a > 8) {
    if(a == b || b < a) {
        System.out.println("Hi");
    }
    else {
        System.out.println("Bye");
    }
}
else {
    System.out.println("Got it");
}

Choices

  • Hi
  • Bye
  • Got it
  • None

Question

Predict the output of the following code?

if(true) {
   if(true) {
       if(false) {
           System.out.println("Hey there");
       }
   }
   else {
       System.out.println("Hello");
   }
}
else {
   System.out.println(10 / 0);
}

Choices

  • Hey there
  • Hello
  • No output
  • Error

Explanation:

We are not getting an error because the inner if statement with the false condition is not executed due to the if condition being false. Therefore, the else block following it is also not executed. The program simply moves on to the next line, which is outside of any control structures and executes the statement System.out.println("Hello"); as expected.

The else block following the outer if statement is also not executed since the condition of the outer if statement is true, and the program again moves to the next line and executes the statement System.out.println("Hello");

Categorise the number

Ques: Given a number, classify it as follows:

  • +ve and even
  • +ve and odd
  • -ve and even
  • -ve and odd

Example :

Input: 

public static void main(){
    Scanner scn = new Scanner(System.in);
    int n = scn.nextInt();
    if(num > 0){
        if(num % 2 == 0){
            SOPln("Positive and even");
        }
        else{
            SOPln("Positive and odd");
        }
    }
    else{
        if(num % 2 == 0){
            SOPln("Negative and even");
        }
        else{
            SOPln("Negative and odd");
        }   
    }
}

Scope of a Variable

It defines the point till where you can use the variable. You can only use a variable till the closing bracket of the block in which it was created.

Example 1:

public static void main(){

    int x;
    x = 5;

    int y;
    y = 20

}

Scope of variable x: Line 4 to 10

Scope of variable y: Line 7 to 10

Example 2:

public static void main(){

    int x = 10;
    if(x == 10){
        int y = 5;
        SOP(y);
    }
    int z = 9;

}

Scope of variable x: Line 3 to 10

Scope of variable y: Line 5 to 7

Scope of variable z: Line 8 to 10

Example 3:

public static void main(){
    int a = 10;
    {
        a = 20;
    }
    SOP(a); 

}

Scope of variable a: Line 2 to 8 Also the code will print 20 as the changes done in the variable values are not restricted to that block in which the change is done. But the life of the variable is restricted to the block in which it was created.

Example 4:

public static void main(){
    int x = 10;
    {
        int y = 20;
        SOP(x + " " + y);
    }
    {
        SOP(x + " " + y); 
        // This line will give error as y is not present in its scope
    } 

}

Example 5: Redefining variable error

public static void main(){
    int a = 90;
    {
        int a = 7; 
        // This line will give error as variable a is already defined in this scope
        SOPln(a);
    }

}

Question

Predict the output of the following code:

public static void main(String args[]) {
    int x = 10;
    {
        int y = 20;
        System.out.println(x + " " + y);
    }
    {
        System.out.println(x + " " + y);
    }
    System.out.println(x + " " + y);
}

Choices

  • Error
  • 10 20
    10 20
    10 20
  • 10 20 10 20 10 20

Question

Predict the output of the following code:

public static void main(){
    int x = 10, y = 20;
    {
        SOP(x + " " + y);
    }
    {
        x = 15;
        SOPln(x + " " + y);
    }
    SOPln(x + " " + y);
}

Choices

  • 10 20
    15 20
    10 20
  • Error
  • 10 20
    15 20
    15 20
  • inky pinky ponky

Question

Predict the output of the following code: 

if(true){
    int x = 10;
    SOPln("Value of x is " + x);
    x ++ ;
}
SOPln("Value of x is " + x);

Choices

  • Value of x is 10
    Value of x is 11
  • Value of x is 10
    Value of x is 0
  • Value of x is 10
    Value of x is 10
  • Error

Question

Predict the output of the following code: 

int a = 0;
{
    int b = 10;
    SOPln("b = " + b);
    int c = a + b;
    SOPln("c = " + c);
}
a = c + b; 
SOPln("a = " + a);

Choices

  • a = 20
    b = 10
    c = 10
  • b = 10
    c = 10
    a = 20
  • Error

Explanation: Error b and c are out of the scope

Question

Predict the output of the following code: 

int a = 10, b = 5;
if(true){
    int c = a * b;
}
SOPln(c);

Choices

  • 50
  • Error
  • Need Coffee!!

Explanation: Error the variable c is out of the scope