Detailed Explanation of Core Points for C++ GESP Level 3
In the GESP Level 3 exam, C++ is the core language assessed, and mastering the key points is crucial for success. Today, we will systematically outline the important and frequently tested knowledge points in the GESP Level 3 exam, combined with real questions and practice problems, to help you prepare efficiently!
Detailed Explanation of Core Points
1. Data Encoding: Sign-Magnitude, One’s Complement, and Two’s Complement
In the world of computers, data encoding is the foundation of digital storage and computation.
- Sign-Magnitude: Represented in the form of “sign bit + absolute value”. For example, the sign-magnitude representation of -5 is
<span>10000101</span>, where the highest bit<span>1</span>indicates a negative number, and the remaining bits represent the absolute value. However, sign-magnitude has a special issue, as it has both<span>+0</span>(<span>00000000</span>) and<span>-0</span>(<span>10000000</span>). - One’s Complement: The sign bit remains unchanged, while all other bits are inverted. Therefore, the one’s complement of -5 is
<span>11111010</span>. - Two’s Complement: One is added to the one’s complement, so the two’s complement of -5 is
<span>11111011</span>. The two’s complement plays an important role in computer storage and computation, solving some issues of sign-magnitude arithmetic and making calculations more efficient and accurate.
2. Base Conversion: Binary, Octal, Decimal, and Hexadecimal
Conversion between different bases is a high-frequency topic in the exam, and mastering the conversion methods is crucial.
- Binary and Decimal Conversion: You can use short division with remainder (decimal to binary) or the positional expansion method (binary to decimal).
- Binary and Hexadecimal Conversion: Group the binary number into sets of 4 bits for conversion; for example,
<span>1011</span>converts to hexadecimal as<span>B</span>. - High-Frequency Question Types: For instance, converting the binary
<span>11.01</span>to decimal results in<span>3.25</span>; or comparing hexadecimal<span>0xf</span>with octal<span>015</span>, determining if they are equal (result is<span>false</span>).
3. Bitwise Operations: AND, OR, NOT, XOR, Left Shift, Right Shift
Bitwise operations have a wide range of applications in actual programming.
- Application Scenarios: Mask operations (for example,
<span>3 | 16 = 19</span>), using bitwise operations to achieve fast multiplication and division by 2 (left shift is equivalent to multiplying by 2, right shift is equivalent to dividing by 2). - Common Pitfalls: When performing arithmetic right shifts, the sign bit needs to be preserved; for example,
<span>-4 >> 1</span>results in<span>-2</span>, not<span>2</span>.
4. Algorithms and Descriptions: Natural Language, Flowcharts, Pseudocode
- Enumeration Method: Solving problems by exhaustively listing all possible solutions, commonly used in prime number determination, permutations, and combinations.
- Simulation Method: Implementing logic according to actual steps, such as simulating the process of saving money, from depositing, withdrawing, to calculating the balance and other operations.
5. C++ One-Dimensional Arrays and String Processing
- Array Operations: Traversing, sorting, and searching one-dimensional arrays are common operations. For example, counting the maximum value in an array or performing word frequency statistics.
- String Functions:
<span>tolower()</span>is used for case conversion,<span>substr()</span>can achieve string splitting, and<span>find()</span>is used to search for a specified string.
GESP Level 3 Historical Exam Questions Classification Table
| Question Number | Knowledge Point | Question Name |
|---|---|---|
| B3925 | Base and Complement | Cat Dividing Fish (Base Conversion) |
| B3868 | Base Judgment | |
| B3956 | Bitwise Operations | Letter Summation (ASCII and Bitwise Operations) |
| B4003 | Shifting (Right Shift Operation) | |
| B3843 | Enumeration and Simulation | Password Compliance Check (Conditional Enumeration) |
| B3957 | Perfect Square (Enumeration Optimization) | |
| B3842 | String Processing | Spring Outing (String Splitting and Statistics) |
| B4262 | Word Frequency Statistics (Case Normalization and Hashing) |
Luogu GESP Level 3 Practice Questions of the Same Difficulty (50 Selected Questions)
| Question Number | Question Name | Knowledge Point |
|---|---|---|
| P1036 | Selecting Numbers | Enumeration Method + Prime Judgment |
| P1308 | Counting Words | String Search and Conversion |
| P1598 | Vertical Histogram | String Statistics and Formatted Output |
| P1046 | Tao Tao Picking Apples | One-Dimensional Array Traversal |
| P1427 | Little Fish’s Number Game | Array Reversal Operation |
| P5657 | Bus Transfer | Simulation Method + Queue Application |
| P1012 | Combining Numbers | String Sorting and Concatenation |
| P1059 | Ming Ming’s Random Number | Array Deduplication and Sorting |
| P1068 | Score Line Setting | Struct Sorting and Simulation |
| P1553 | Number Reversal (Upgraded Version) | String Splitting and Reversal |
Preparation Suggestions
Preparation Suggestions
- Foundation Consolidation Focus on mastering the two high-frequency topics of base conversion and bitwise operations, ensuring a solid grasp of basic concepts and operations.
- Real Question Practice Carefully complete past exam questions, such as the 2023 December question on two’s complement calculation, and analyze mistakes to identify weak knowledge areas.
- Simulation Training Conduct timed simulation question training, optimizing time allocation to improve answering speed and accuracy.
Luogu GESP Level 3 Practice Questions of the Same Difficulty (50 Selected Questions)
| Question Number | Question Name | Knowledge Point | Difficulty |
|---|---|---|---|
| Base Conversion | |||
| P1143 | Base Conversion | Hexadecimal and Decimal Conversion | Beginner- |
| P1062 | Sequence | Binary Properties and Recursion | Beginner- |
| P1017 | Base Number | Negative Base Conversion | Beginner/Intermediate- |
| Bitwise Operations | |||
| P1100 | High-Low Bit Swap | Bitwise Operations and Shifting | Beginner- |
| P5657 | Bus Transfer | Bit Mask and State Judgment | Beginner- |
| P2114 | Bitwise Operation Practice Questions | AND/OR/XOR Comprehensive Application | Beginner- |
| String Processing | |||
| P1308 | Counting Words | String Search and Case Handling | Beginner- |
| P1553 | Number Reversal (Upgraded Version) | String Splitting and Reversal | Beginner- |
| P1598 | Vertical Histogram | Character Statistics and Formatted Output | Beginner- |
| One-Dimensional Array | |||
| P1046 | Tao Tao Picking Apples | Array Traversal and Condition Judgment | Entry |
| P1427 | Little Fish’s Number Game | Array Reversal Operation | Entry |
| P1059 | Ming Ming’s Random Number | Array Deduplication and Sorting | Entry |
| Enumeration and Simulation | |||
| P1036 | Selecting Numbers | Enumeration Combination and Prime Judgment | Beginner- |
| P1152 | Happy Jump | Simulated Difference Calculation | Beginner- |
| P1563 | Toy Puzzle | Circular Array Simulation | Beginner- |
| Comprehensive Application Questions | |||
| P1012 | Combining Numbers | String Sorting and Concatenation | Beginner- |
| P1068 | Score Line Setting | Struct Sorting and Simulation | Beginner- |
| P3956 | Chessboard | Two-Dimensional Array and Path Simulation | Beginner/Intermediate- |
| P1569 | High Precision Subtraction | String Simulation Calculation | Beginner/Intermediate- |
| P1591 | Factorial Code | Large Number Calculation and Digit Statistics | Beginner/Intermediate- |
I hope this guide can provide strong assistance for your GESP Level 3 preparation, and I wish everyone excellent results in the exam! Start your problem-solving journey now!