Code Snippets-based MCQs

Nested Loops

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Easy Level MCQs
MCQs on Common Problems
Tricky MCQs

Easy Level MCQs - Nested Loops

Below are 30 simple questions about nested loops in Java:

Given the following code snippet, what will be the output?
```
 for (int i = 0; i < 2; i++) {
     for (int j = 0; j < 2; j++) {
         System.out.println("i=" + i + ", j=" + j);
     }
 }
```
i=0, j=0 and i=0, j=1
i=0, j=0; i=0, j=1; i=1, j=0; i=1, j=1
i=1, j=1 only
No output

Answer

i=0, j=0; i=0, j=1; i=1, j=0; i=1, j=1

Given the following code snippet, what is printed to the console?

 int count = 0;
 for (int i = 0; i < 2; i++) {
     for (int j = 0; j < 3; j++) {
         count++;
     }
 }
 System.out.println(count);

Answer

6
(Loop runs 2 times in the outer loop and 3 times in the inner loop: 2 * 3 = 6)

What will be the output of the following code snippet?

 int sum = 0;
 for (int i = 1; i <= 2; i++) {
     for (int j = 1; j <= 2; j++) {
         sum += (i + j);
     }
 }
 System.out.println(sum);

Answer

12
(Expanding: When i=1, j=1 → sum += 2; i=1, j=2 → sum += 3; i=2, j=1 → sum += 3; i=2, j=2 → sum += 4; total = 2+3+3+4 = 12)

Given the following nested loop, what gets printed?

 for (int i = 1; i <= 2; i++) {
     for (int j = 1; j <= 2; j++) {
         System.out.print(i * j + " ");
     }
 }

Answer

1 2 2 4
(i=1, j=1 → 1; i=1, j=2 → 2; i=2, j=1 → 2; i=2, j=2 → 4)

What will be the output of the following code?

 int total = 0;
 for (int i = 0; i < 3; i++) {
     for (int j = i; j < 3; j++) {
         total++;
     }
 }
 System.out.println(total);

Answer

6
(Explanation: i=0 → j runs 0 to 2 (3 times), i=1 → j runs 1 to 2 (2 times), i=2 → j runs 2 to 2 (1 time). Total = 3+2+1 = 6)

What will be printed to the console?

 for (int i = 1; i <= 2; i++) {
     for (int j = 3; j >= 2; j--) {
         System.out.print((i + j) + " ");
     }
 }

Answer

4 3 5 4
(When i=1: j=3 → 4, j=2 → 3; when i=2: j=3 → 5, j=2 → 4)

Given the following code, how many stars (*) get printed?
```
 int count = 0;
 for (int i = 0; i < 2; i++) {
     for (int j = 0; j < 3; j++) {
         System.out.print("*");
         count++;
     }
 }
 System.out.println();
 System.out.println(count);
```
3 stars, then 3 printed as count
4 stars, then 4 printed as count
6 stars, then 6 printed as count
2 stars, then 2 printed as count

Answer

6 stars, then 6 as count
(Because 2 (outer loop) × 3 (inner loop) = 6 total iterations)

What is the printed result?

 for (int i = 0; i < 2; i++) {
     for (int j = 0; j < 2; j++) {
         if (j == 1) {
             System.out.print("X ");
         } else {
             System.out.print("O ");
         }
     }
 }

Answer

O X O X
(When i=0: j=0 → O, j=1 → X; when i=1: j=0 → O, j=1 → X)

How many times does the string “Hello” print?

 int count = 0;
 for (int i = 0; i < 3; i++) {
     for (int j = 0; j < i; j++) {
         System.out.println("Hello");
         count++;
     }
 }
 System.out.println(count);

Answer

3 times
(Explanation: i=0 → inner loop runs 0 times, i=1 → inner loop runs 1 time, i=2 → inner loop runs 2 times. Total = 0+1+2 = 3)

What does the following code print out?
```
for (int i = 1; i <= 2; i++) {
    for (int j = 2; j <= 3; j++) {
        System.out.print(i + j + " ");
    }
}
```
2 3 3 4
3 4 3 4
2 3 4 5
3 4 4 5

Answer

3 4 4 5
(First iteration i=1: j=2 → 3, j=3 → 4; second iteration i=2: j=2 → 4, j=3 → 5)

How many times does the string "Hello" print?

int count = 0;
for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 2; j++) {
        System.out.println("Hello");
        count++;
    }
}
System.out.println(count);

Answer

4 times
(Explanation: Outer loop runs 2 times; inner loop runs 2 times for each outer iteration. Total = 2 × 2 = 4)

What is printed by this code?

for (int i = 1; i <= 2; i++) {
    for (int j = 1; j <= 2; j++) {
        System.out.print(i + j + " ");
    }
}

Answer

2 3 3 4
(First iteration: i=1, j=1→2, j=2→3; second iteration: i=2, j=1→3, j=2→4)

How many times will the inner loop run in total?

int totalIterations = 0;
for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 2; j++) {
        totalIterations++;
    }
}
System.out.println(totalIterations);

Answer

6
(Outer loop: 3 iterations; inner loop: 2 iterations per outer loop. 3 × 2 = 6)

What does this code print?

for (int i = 0; i < 2; i++) {
    for (int j = i; j < 2; j++) {
        System.out.print("X ");
    }
    System.out.println();
}

Answer

  X X
  X

(Explanation: For i=0: j=0 to 1 → prints “X X”. For i=1: j=1 → prints “X”.)

Which statement best describes the value of count?

int count = 0;
for (int i = 0; i < 2; i++) {
    for (int j = 0; j <= i; j++) {
        count++;
    }
}
System.out.println(count);

Answer

3
(Explanation: i=0 → inner loop runs 1 time; i=1 → inner loop runs 2 times. Total = 1+2 = 3)

What output is produced?

for (int i = 1; i <= 2; i++) {
    for (int j = 1; j <= 3; j++) {
        System.out.print((i * j) + " ");
    }
    System.out.println();
}

Answer

  1 2 3
  2 4 6

(First row: i=1 → 1×1, 1×2, 1×3; second row: i=2 → 2×1, 2×2, 2×3)

What is the final value of result?
```
int result = 1;
for (int i = 1; i <= 2; i++) {
    for (int j = 1; j <= 2; j++) {
        result += (i + j);
    }
}
System.out.println(result);
```
5
9
11
13

Answer

13
Explanation: Loops run 4 times total. Each iteration adds (i+j). Iterations:
Iteration 1: result=1,i=1,j=1 → result+=1+1=3 Iteration 2: result=3,i=1,j=2 → result+=1+2=6 Iteration 3: result=6,i=2,j=1 → result+=2+1=9 Iteration 4: result=9,i=2,j=2 → result+=2+2=13

What does this nested loop print on each line?

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 2; j++) {
        System.out.print(i + "," + j + " ");
    }
    System.out.println();
}

Answer

  0,0 0,1
  1,0 1,1
  2,0 2,1

How many times does the inner statement execute?

int times = 0;
for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 3; j++) {
        if (i == j) {
            times++;
        }
    }
}
System.out.println(times);

Answer

3
(Checks when i == j for i,j in {1,2,3}, which happens at (1,1), (2,2), (3,3))

What is the output of this nested loop?

for (int i = 1; i < 3; i++) {
    for (int j = 1; j <= i; j++) {
        System.out.print("*");
    }
    System.out.println();
}

Answer

Which numbers are printed?

for (int i = 0; i < 2; i++) {
    for (int j = 2; j > 0; j--) {
        System.out.print(i + j + " ");
    }
    System.out.println();
}

Answer

  2 1
  3 2

(When i=0, j=2→2, j=1→1; When i=1, j=2→3, j=1→2)

What does this code output?

for (int i = 1; i <= 3; i++) {
    for (int j = 3; j >= i; j--) {
        System.out.print("#");
    }
    System.out.println();
}

Answer

  ###
  ##
  #

What is printed?

int i = 0;
while (i < 2) {
    int j = 0;
    while (j < 2) {
        System.out.print(i + j + " ");
        j++;
    }
    i++;
}

Answer

0 1 1 2
(Explanation: i=0 → j=0→0, j=1→1; i=1 → j=0→1, j=1→2)

How many lines are printed in total?

int lines = 0;
for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 2; j++) {
        System.out.println("Line");
        lines++;
    }
}
System.out.println(lines);

Answer

4
(2 × 2 = 4 total prints in nested loops)

What is printed?
```
for (int i = 1; i <= 2; i++) {
    for (int j = i; j <= 2; j++) {
        System.out.print((i + j) + " ");
    }
    System.out.println();
}
```
2 3
3 4

2 3
4

1 2
1

2 3 4
(Single line)
Answer
```
  2 3
  4
```
Explanation: i=1→ j=1..2→ sums=2,3; i=2→ j=2..2→ sum=4 (i+j=2+2=4) but note j=2 only one iteration => 3 + 4? We need to be precise.
Iteration 1: For i=1: j=1..2 => i+j = 2, 3 → prints “2 3”
Iteration 2: For i=2: j=2..2 => i+j = 4 → prints “4”
Actually that prints:
First line: 2 3
Second line: 4
So it’s 2 3 on the first line, 4 on the second line.

Which of the following is the correct final output?

int sum = 0;
for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 3; j++) {
        sum += j;
    }
}
System.out.println(sum);

Answer

6
(Inner loop j runs 3 times: j=0,1,2 → sum of j = 3. Outer loop runs 2 times, total sum = 3+3 = 6)

What gets printed here?

for (int i = 2; i > 0; i--) {
    for (int j = 0; j < i; j++) {
        System.out.print("*");
    }
    System.out.println();
}

Answer

How many times does the if condition succeed?

int matches = 0;
for (int i = 1; i <= 2; i++) {
    for (int j = 1; j <= 2; j++) {
        if ((i + j) % 2 == 0) {
            matches++;
        }
    }
}
System.out.println(matches);

Answer

2
(All possible sums of (i+j) with i,j ∈ {1,2} are 2,3,3,4. Even sums are 2 and 4 → 2 matches.)

What is printed by this nested while loop?

int i = 0;
while (i < 2) {
    int j = 2;
    while (j > 0) {
        System.out.print((i + j) + " ");
        j--;
    }
    i++;
    System.out.println();
}

Answer

  2 1
  3 2

(Explanation: i=0 → j=2..1 => sums=2,1; i=1 → j=2..1 => sums=3,2)

What does the following code produce?

for (int i = 0; i < 3; i++) {
    for (int j = i; j < 3; j++) {
        System.out.print("*");
    }
    System.out.println();
}

Answer

  *
      
  *

(Explanation: i=0→ j=0..2 => 3 stars; i=1→ j=1..2 => 2 stars; i=2→ j=2..2 => 1 star)

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MCQs on Common Problems

Below are 20 questions, each featuring a Java code snippet relevant to common problems such as digit-wise calculations, character pattern printing, prime series, etc.

What is the final value of sum?

int n = 123;
int sum = 0;
while (n > 0) {
    int digit = n % 10;
    sum += digit;
    n /= 10;
}
System.out.println(sum);

Answer

6
(Explanation: Digits are 3, 2, and 1. Sum = 3 + 2 + 1 = 6)

What is the output of this code?

for (int num = 1; num <= 10; num++) {
    boolean isPrime = true;
    if (num <= 1) {
        isPrime = false;
    }
    for (int i = 2; i <= num / 2; i++) {
        if (num % i == 0) {
            isPrime = false;
            break;
        }
    }
    if (isPrime) {
        System.out.print(num + " ");
    }
}

Answer

4 primes
(They are 2, 3, 5, 7)

What does the following code snippet print?

int n = 4;
long fact = 1;
for (int i = 1; i <= n; i++) {
    fact = fact * i;
}
System.out.println(fact);

Answer

24
(Explanation: 4! = 4 × 3 × 2 × 1 = 24)

What is the output of this code snippet?

int a = 0, b = 1;
System.out.print(a + " " + b + " ");
for(int i = 3; i <= 5; i++){
    int c = a + b;
    System.out.print(c + " ");
    a = b;
    b = c;
}

Answer

0 1 1 2 3
(First five Fibonacci terms starting with 0, 1)

What does this code print?

int num = 230;
int rev = 0;
while (num > 0) {
    int digit = num % 10;
    rev = rev * 10 + digit;
    num /= 10;
}
System.out.println(rev);

Answer

32
(Leading zeros are dropped in integer operations)

How many times does "Java" print?

int number = 129;
while (number > 0) {
    int digit = number % 10;
    if (digit % 2 == 0) {
        System.out.println("Java");
    }
    number /= 10;
}

Answer

1 time
(Digits are 9 (odd), 2 (even), 1 (odd). Only 2 triggers the print)

What character pattern is printed by this code?

for (char c = 'A'; c <= 'C'; c++) {
    for (char d = 'A'; d <= c; d++) {
        System.out.print(d + " ");
    }
    System.out.println();
}

Answer

  A
  A B
  A B C

What is the output?

int num = 151;
int original = num;
int reverse = 0;
while (num > 0) {
    int digit = num % 10;
    reverse = reverse * 10 + digit;
    num /= 10;
}
if (reverse == original) {
    System.out.println("Palindrome");
} else {
    System.out.println("Not Palindrome");
}

Answer

Palindrome

How many prime numbers will be printed up to 20?

for (int num = 2; num <= 20; num++) {
    boolean isPrime = true;
    for (int i = 2; i <= Math.sqrt(num); i++) {
        if (num % i == 0) {
            isPrime = false;
            break;
        }
    }
    if (isPrime) {
        System.out.print(num + " ");
    }
}

Answer

8
(The primes up to 20 are 2,3,5,7,11,13,17,19)

What is printed by this numeric pattern code?

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= i; j++) {
        System.out.print(j);
    }
    System.out.println();
}

Answer

  1
  12
  123

How many digits of 407 does the code consider to check if it’s an Armstrong number?

int n = 407;
int temp = n;
int sumOfCubes = 0;
while (temp > 0) {
    int digit = temp % 10;
    sumOfCubes += digit * digit * digit;
    temp /= 10;
}
System.out.println(sumOfCubes == n);

Answer

3
(Digits are 7, 0, 4 in the loop)

What does this code snippet print?

int num = 999;
int sum = 0;
for (; num > 0; num /= 10) {
    sum += (num % 10);
}
System.out.println(sum);

Answer

27
(9 + 9 + 9 = 27)

What is the outpu?

for (int i = 1; i <= 10; i++) {
    if (i % 3 == 0) {
        System.out.print(i + " ");
    }
}

Answer

3 6 9

Which numbers are printed?

for (int num = 8; num <= 13; num++) {
    boolean prime = true;
    for (int i = 2; i < num; i++) {
        if (num % i == 0) {
            prime = false;
            break;
        }
    }
    if (prime && num > 1) {
        System.out.print(num + " ");
    }
}

Answer

11 13
(8, 9, 10, 12 are not prime)

What pattern of asterisks is printed?

for (int i = 3; i > 0; i--) {
    for (int j = 0; j < i; j++) {
        System.out.print("*");
    }
    System.out.println();
}

Answer

  ***
  **
  *

Which lines will be printed?
```
int number = 145;
while (number > 0) {
    int digit = number % 10;
    System.out.println(digit * 2);
    number /= 10;
}
```
10, 8, 2 (in that order)
2, 8, 10 (in that order)
10, 4, 2 (in that order)
2, 4, 10 (in that order)

Answer

10, 8, 2 (in that order)
(Digits: 5→10, 4→8, 1→2)

How many characters are printed here?

int count = 0;
for (char c = 'A'; c <= 'Z'; c++) {
    System.out.print(c + " ");
    count++;
}
System.out.println("\n" + count);

Answer

26
(A through Z is 26 letters)

What does the code print for the number 5?

int x = 5;
boolean prime = true;
for (int i = 2; i < x; i++) {
    if (x % i == 0) {
        prime = false;
        break;
    }
}
if (prime && x > 1) {
    System.out.println("Prime");
} else {
    System.out.println("Not Prime");
}

Answer

Prime

What pattern is printed?

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 3; j++) {
        if (j < i) {
            System.out.print(" ");
        } else {
            System.out.print("*");
        }
    }
    System.out.println();
}

Answer

  *
       
    *

(Explanation: For row i, spaces are printed for j < i, then * for j ≥ i.)

What does this code output for n=6 (printing prime factors)?

int n = 6;
for (int i = 2; i <= n; i++) {
    while (n % i == 0) {
        System.out.print(i + " ");
        n /= i;
    }
}

Answer

2 3
(Prime factors of 6 are 2 and 3)

Code Snippets-based MCQs

Nested Loops

Easy Level MCQs - Nested Loops

MCQs on Common Problems

Tricky MCQs