Summary of C++ Programming Preliminary Questions for the 2025 Information Literacy Competition for Elementary School Students

2025 Youth Information Literacy Competition Algorithm Creativity C++

1.

【Multiple Choice Questions】 (5 points each)

Question 1

In C++, which symbol represents the logical operator “or”?

A. ||

B. &

C. ==

D. @

Question 2

What is the output of the following code when the input is 3? ( )

A. -n

B. 0

C. 9

D. 81

Question 3

Which of the following options outputs 0? ( )

A. cout << “5 – 5”;

B. cout << 5 – 5;

C. cout << 2 * 3;

D. cout << 7 / 2;

Question 4

What is the output of the following code segment? ( )

cout << 10 % 3;

A. 1

B. 2

C. 5

D. 10

Question 5

Which of the following is not part of the basic C++ program structure? ( )

A. Header files

B. Namespace

C. Main function

D. Program development time: 2025-03-23

Question 6

Read the following program, what is the output when the input is 1 5? ( )

int a,b;

cin >> a >> b;

a += b;

b *= a;

cout << a << ” ” << b << endl;

A. 1 5

B. 6 5

C. 5 6

D. 6 30

Question 7

What is the expression to get the digit in the tens place of a four-digit integer in a C++ program? ( )

A. number / 1000

B. number / 100 % 10

C. number / 10 % 10

D. number % 10

Question 8

The following program separates the digits of a positive integer n and prints each digit in reverse order. What should be filled in at position ①? ( )

A. n > 0

B. n >= 0

C. n < 0

D. n <= 0

Question 9

The following program outputs “1 4 7 10”. Which option correctly completes the code at position ①? ( )

A. i++

B. i *= 2

C. i += 3

D. i * 2

Question 10

What is the output of the following code? ( )

A. 1

B. 2 4

C. 1 3 5

D. 1 2 3 4

Question 11

The following diagram shows the output pattern when n = 5. What should be filled in at position ① to output a special right triangle with n+1 rows? ( )

A. j <= 2 * i

B. j <= i

C. j <= 2 * i – 1

D. j <= 2 * i + 1

Question 12

What is the output of the following program segment? ( )

A. 40

B. 60

C. 90

D. 120

Question 13

What is the output of the following code? ( )

A.

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

B.

5 4 3 2 1

5 4 3 2 1

5 4 3 2 1

5 4 3 2 1

C.

1 2 3 4

1 2 3 4

1 2 3 4

1 2 3 4

D.

5 4 3 2 1

5 4 3 2 1

5 4 3 2 1

Question 14

What is the output when the following program is executed with input 5? ( )

A. 5

B. 30

C. 55

D. 85

Question 15

What is the output when the following program is executed with input 6? ( )

A. QWER

B. WERQ

C. ERQW

D. RQWE

2.

【True/False Questions】 (5 points each)

Question 16

In C++, && represents the logical operator “or”.

True

False

Question 17

In C++, you can define and initialize an array like this: int c[3]={1,2,3,4,5}

True

False

Question 18

In C++, the index of a one-dimensional array starts from 0.

True

False

Question 19

Code segment

The final value is -1.

True

False

Question 20

After defining int arr[5]; executing arr[5]=5 will not cause an array out of bounds.

True

False

3.

Reference Answers

Question 1: Answer: A

|| is or, && is and

Question 2: Answer: B

n-3=3-3=0

Question 3: Answer: B

5-5=0

Question 4: Answer: A

10 ÷ 3 = 1…1, so the remainder is 1

Question 5: Answer: D

Question 6: Answer: D

a: a+=b 1+5=6

b: 5*6=30

Question 7: Answer: C

number/10 removes the unit digit

number%10 keeps the unit digit (i.e., the tens digit)

Question 8: Answer: A

while(n>0) n>0 repeats until n=0 exits the loop

while(n) until n=0 exits the loop

while(n!=0) n not equal to 0 repeats

Question 9: Answer: D

i starts from 1 to 10, if it outputs 1 4 7 10

then the interval is 3, i+=3;

Question 10: Answer: C

i: 1,2,3,4,5

If it is a multiple of 2 (even), skip, otherwise output, hence 1,3,5

Question 11: Answer: B

i: 1-5, so for row count 1,2,3,4,5

j: j=1; j=i, j++, same number per row

*

**

***

****

*****

Question 12: Answer: A

i loops 5 times, j loops 4 times, k loops 2 times. So total loops 5*4*2=40

Question 13: Answer: B

Key inner loop j: from 5 to 1, outer loop i loops 4 times. So select B

Question 14: Answer: C

Input 5. Loop 5 times: 1*1, 2*2, 3*3, 4*4, 5*5, total sum is 55

Question 15: Answer: A

Multiples of 2 output QWER

Multiples of 3 output WERQ

Multiples of 5 output ERQW

Otherwise, other multiples output RQWE

6 is a multiple of 2, hence output QWER

Question 16: Answer: False

and

Question 17: Answer: False

Array out of bounds, at most 3 numbers

Question 18: Answer: True

Question 19: Answer: True

i>0 repeats until less than or equal to 0, exits the loop

Change process i=5, i=3, i=1, i=-1.

Question 20: Answer: False

Array index: 0, 1, 2, 3, 4, and there is no arr[5].