JAVA FOR LOOP

 

Great choice 👍 Class 9 ICSE – Java for Loop
I’ll explain low → high level, exactly as you want for classroom teaching.

🔹 PART 1: MCQs (Low → Moderate Level)

1. Which loop is used when the number of iterations is known?

A. while
B. do-while
C. for
D. if

✅ Answer: C

2. What is the correct syntax of a for loop?

A. for(initialization; condition; increment)
B. for(condition; increment; initialization)
C. for(increment; condition; initialization)
D. for(initialization, condition, increment)

✅ Answer: A

3. How many times will this loop run?

for(int i=1; i<=5; i++)

A. 4
B. 5
C. 6
D. Infinite

✅ Answer: B

4. Which part of the for loop runs only once?

A. Condition
B. Increment
C. Initialization
D. Loop body

✅ Answer: C

5. Which operator is commonly used to increase loop value by 1?

A. +=
B. ++
C. --
D. ==

✅ Answer: B

6. What will be the final value of i?

for(int i=0; i<3; i++)

A. 2
B. 3
C. 1
D. 0

✅ Answer: B

7. Which keyword is used to stop a loop immediately?

A. continue
B. stop
C. break
D. exit

✅ Answer: C

8. Which loop checks the condition first?

A. do-while
B. while
C. for
D. Both B and C

✅ Answer: D

9. What happens if the condition is always true?

A. Loop runs once
B. Compilation error
C. Infinite loop
D. Loop stops automatically

✅ Answer: C

10. Which variable is generally used in a for loop?

A. char
B. boolean
C. int
D. double

✅ Answer: C

🔹 PART 2: Important Points for for Loop (MCQ Focus)

These points often come in ICSE MCQs 👇

  1. for loop is an entry-controlled loop.
  2. Initialization executes only once.
  3. Condition is checked before every iteration.
  4. Increment/Decrement executes after loop body.
  5. If condition is false initially, loop runs zero times.
  6. break stops the loop completely.
  7. continue skips the current iteration.
  8. Loop variable is usually of type int.
  9. Multiple variables can be used in a for loop.
  10. Semicolon ; is compulsory between parts.

🔹 PART 3: Basic → High Level CODE (NO FULL PROGRAM)

🟢 EASY LEVEL (3)

1️⃣ Print numbers 1 to 5

for(int i=1; i<=5; i++)

    System.out.println(i);

2️⃣ Print Hello 3 times

for(int i=1; i<=3; i++)

    System.out.println("Hello");

3️⃣ Print even numbers till 10

for(int i=2; i<=10; i+=2)

    System.out.println(i);

🟡 NORMAL LEVEL (3)

4️⃣ Print numbers from 10 to 1

for(int i=10; i>=1; i--)

    System.out.println(i);

5️⃣ Sum of first 5 numbers

int sum = 0;

for(int i=1; i<=5; i++)

    sum += i;

6️⃣ Print square of numbers 1 to 5

for(int i=1; i<=5; i++)

    System.out.println(i*i);

🔴 HARD LEVEL (4)

7️⃣ Count digits in a number

int count = 0;

for(; n>0; n/=10)

    count++;

8️⃣ Reverse a number

int rev = 0;

for(; n>0; n/=10)

    rev = rev*10 + n%10;

9️⃣ Check palindrome logic

for(; n>0; n/=10)

    rev = rev*10 + n%10;

🔟 Nested for loop (pattern logic)

for(int i=1; i<=3; i++)

    for(int j=1; j<=i; j++)

        System.out.print("*");

🎯 Teaching Tip for You (as ICSE Teacher)

Start with:
👉 Real-life example (attendance count, roll numbers)
👉 Then MCQ
👉 Then EASY code
👉 Finally HARD logic

If you want, I can also give:

  • Board-exam MCQs
  • Worksheet
  • Blackboard explanation script
  • Homework questions

Just tell me 👍

🔹 PART 1: MCQs (Low → Moderate Level)

1. Which loop is used when the number of iterations is known?

A. while
B. do-while
C. for
D. if

✅ Answer: C

2. What is the correct syntax of a for loop?

A. for(initialization; condition; increment)
B. for(condition; increment; initialization)
C. for(increment; condition; initialization)
D. for(initialization, condition, increment)

✅ Answer: A

3. How many times will this loop run?

for(int i=1; i<=5; i++)

A. 4
B. 5
C. 6
D. Infinite

✅ Answer: B

4. Which part of the for loop runs only once?

A. Condition
B. Increment
C. Initialization
D. Loop body

✅ Answer: C

5. Which operator is commonly used to increase loop value by 1?

A. +=
B. ++
C. --
D. ==

✅ Answer: B

6. What will be the final value of i?

for(int i=0; i<3; i++)

A. 2
B. 3
C. 1
D. 0

✅ Answer: B

7. Which keyword is used to stop a loop immediately?

A. continue
B. stop
C. break
D. exit

✅ Answer: C

8. Which loop checks the condition first?

A. do-while
B. while
C. for
D. Both B and C

✅ Answer: D

9. What happens if the condition is always true?

A. Loop runs once
B. Compilation error
C. Infinite loop
D. Loop stops automatically

✅ Answer: C

10. Which variable is generally used in a for loop?

A. char
B. boolean
C. int
D. double

✅ Answer: C

🔹 PART 2: Important Points for for Loop (MCQ Focus)

  1. for loop is an entry-controlled loop.
  2. It is used when the number of iterations is known.
  3. Initialization runs only once.
  4. Condition is checked before every iteration.
  5. Increment/Decrement runs after the loop body.
  6. If the condition is false initially, loop executes zero times.
  7. break terminates the loop immediately.
  8. continue skips the current iteration.
  9. Multiple statements can be written using { }.
  10. Nested for loop means loop inside another loop.

🔹 PART 3: Codes (Basic → High Level)

👉 NOTE FOR STUDENTS:
✍️ Write the TOTAL PROGRAM with OUTPUT in the notebook.

🟢 EASY LEVEL (3 Codes)

1️⃣ Print numbers from 1 to 5

for(int i = 1; i <= 5; i++)

{

    System.out.println(i);

}

Output:

1

2

3

4

5

2️⃣ Print “Hello” 3 times

for(int i = 1; i <= 3; i++)

{

    System.out.println("Hello");

}

Output:

Hello

Hello

Hello

3️⃣ Print even numbers from 2 to 10

for(int i = 2; i <= 10; i += 2)

{

    System.out.println(i);

}

Output:

2

4

6

8

10

🟡 NORMAL LEVEL (3 Codes)

4️⃣ Print numbers from 10 to 1

for(int i = 10; i >= 1; i--)

{

    System.out.println(i);

}

Output:

10

9

8

7

6

5

4

3

2

1

5️⃣ Find sum of first 5 natural numbers

int sum = 0;

for(int i = 1; i <= 5; i++)

{

    sum = sum + i;

}

System.out.println(sum);

Output:

15

6️⃣ Print square of numbers from 1 to 5

for(int i = 1; i <= 5; i++)

{

    System.out.println(i * i);

}

Output:

1

4

9

16

25

🔴 HARD LEVEL (4 Codes)

7️⃣ Count digits in a number

int count = 0;

for(; n > 0; n = n / 10)

{

    count++;

}

System.out.println(count);

Output (Example: n = 456):

3

8️⃣ Reverse a number

int rev = 0;

for(; n > 0; n = n / 10)

{

    rev = rev * 10 + n % 10;

}

System.out.println(rev);

Output (Example: n = 123):

321

9️⃣ Palindrome logic using for loop

int rev = 0, temp = n;

for(; n > 0; n = n / 10)

{

    rev = rev * 10 + n % 10;

}

Output (Example: n = 121):

Palindrome

🔟 Nested for loop (Star pattern)

for(int i = 1; i <= 3; i++)

{

    for(int j = 1; j <= i; j++)

    {

        System.out.print("*");

    }

    System.out.println();

}

Output:

*

**

***

🔹 PART 4: 10 MCQs (Final – Board Practice)

21. Which loop is best when repetitions are fixed?

A. while
B. do-while
C. for
D. if

✅ Answer: C

22. How many times will this loop execute?

for(int i=1; i<5; i++)

A. 3
B. 4
C. 5
D. Infinite

✅ Answer: B

23. What does i++ mean?

A. i = i + 2
B. i = i - 1
C. i = i + 1
D. i = i × 1

✅ Answer: C

24. Which symbol separates parts of for loop?

A. :
B. ,
C. ;
D. .

✅ Answer: C

25. Which loop can be nested?

A. if
B. for
C. while
D. All of these

✅ Answer: D

26. What is the output?

for(int i=1; i<=1; i++)

System.out.println(i);

A. 0
B. 1
C. Infinite
D. Error

✅ Answer: B

27. Which keyword skips one iteration?

A. break
B. skip
C. continue
D. exit

✅ Answer: C

28. Which loop may never execute?

A. for
B. while
C. do-while
D. none

✅ Answer: A

29. Which value is checked again and again?

A. Initialization
B. Condition
C. Increment
D. Variable type

✅ Answer: B

30. Which loop is entry controlled?

A. do-while
B. for
C. switch
D. case

✅ Answer: B


 

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