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1. Suffix expression Example:              2. Calculator core algorithm Solutions 1. Separate infix expression from number and operator 2. Convert infix expression to suffix expression 3. Calculate the final result by suffix expression 3. Separation algorithm idea Initial num variable is empty, scan stringIf a number or decima ...

Exception handling and testing Error type exception handling Example 1 try to execute code that may cause exception exception exception capture exception Example 2 Example 3 finally raise Official python Exception document Code testing Test function Test class Illustrate with examples unit testi ...

The execution order of the pointcuts of different annotations in the slice is: preprocessing, postprocessing, return processing / exception processing, which is well understood. However, if multiple tangent classes are defined and there are the same processing steps in them, if the processing order is n ...

Implement a basic calculator to evaluate the value of a simple string expression. String expressions can contain opening parentheses (, closing parentheses), plus sign +, minus sign -, non negative integers and spaces. Example 1: Input: "1 + 1" Output: 2 Example 2: Input: "2-1 + 2& ...

Problem description Analog program calculator, input the instructions in turn, and the possible instructions include 1. Number: 'NUM X', X is a string containing only uppercase letters and numbers, indicating a current base number 2. Operation instructions: 'ADD', 'SUB', 'MUL', 'DIV' and 'MOD', respec ...

Series Length 1. Spring - IOC - Register Components 2. spring - IOC - Dependent Injection 3. Spring - IOC - Component Scan Rules 4. Spring - IOC - Component Scope, Lazy Loading, Conditional Judgment 5. Spring - IOC - Lifecycle of Components 6. Spring - AOP - Basic Use Preface This article will sor ...

Directory Introduction 01. What is recursion 02. Recursive Three Conditions 03. Fibonacci series 04. Find all files in the specified directory 05.Find 1+2+...+N and 06. Find a factorial of 100 07. Combination of Ordered Numbers 08. Find a multiplier 09. Backpack problem 10. Select a team 11. Hannotta Problem 12. Dichotomy Search 13. Watch out ...

When can't I use the arrow function? 1. Define object method The definition method of object method in JS is to define a property pointing to function on the object. When the method is called, this in the method will point to the object to which the method belongs. 1.1 define literal method //1. Define literal method const calculator = { a ...

Bowen structureCustom functionVariable scopePython built-in functions I. function Functions in Python are collections of statements and expressions. There is no limit to the use of functions, just like other values in Python. For reusable code, you need to write a custom function for reuse. Functions can be divided into nonparametric functio ...

The following completes a simple calculator to calculate through the syntax tree, first defines the structure of a syntax tree, then writes a flex file to parse numbers or symbols, returns itself to symbols, returns numbers to numbers, and assigns a value to d of yylval, which refers to a joint type, and then completes the addition of nodes of ...