The following is what I found compiled with C++. I hope it will be useful to you

TopCoder C++ for C programmers:

C++ is added based on the C language Object-oriented extension. C++ provides many advantages that the traditional C language does not have while maintaining compatibility with the C language, so that people can use C and C++ simultaneously in one program. During the competition, you must use some basic C++ functions to answer questions. Below we briefly introduce some C++ knowledge that programmers who are familiar with C language must know to participate in the competition.

Classes and Methods

The most important new concept added in C++ is the class. Classes can contain methods and variables. When competing, you must write a class that contains at least one method. As an example, consider the following problem definition:

Class: CellTower

Method: best

Parameters: vector , int, int< /p>

Return: int

Method signature: int best(vector <:string> towers, int x, int y)

To answer this question you need to create a name Class for CellTower. This class must contain a method named best. The method best must have three parameters (vector, int, and int) and return an integer (int) value.

Classes are defined using the class keyword. Defining a class is similar in syntax to defining a C structure. To define the class required by the above question, you can use the following code:

class CellTower {

public:

int best(vector towers , int x, int y) {

//Your code

}

};

How and how the method is defined A C function is similar. The keyword public tells the compiler that the method we define can be called by any object. Only then can the test program run your code correctly.

STL

Many classes and functions often used in competitions come from the Standard Template Library, usually abbreviated as STL in English. STL provides a common set of libraries that contain tools ranging from basic character processing to complex sorting algorithms.

To participate in the competition you must be familiar with at least two classes: vector and string.

Includes

Before you use a class in STL, you must include the corresponding header file in your code. The vector class comes from the header file "vector"; the string class comes from "string". You also need to add the following line to your code:

This line tells the compiler to look for classes in the std namespace.

Vector

Vector is used in C++ to replace C arrays. Vector solves many problems of traditional C language arrays. Vector can query the current array size and dynamically adjust the size. A vector can be declared using vector, where type is the type of the variable stored in the vector. For example, if you want to create a vector containing int, you can use:

vector myVar;

The size of the newly created vector is 0. To declare a vector of another size, you can use:

vector myVar(10);

In this example the newly created vector has a size of 10.

To set or read an item in a vector, you can use a syntax similar to that used for arrays in C:

vector myVar(10);

myVar[0] = 1; //Set the item at position 0 to 1

printf("%i", myVar[0]); //Output 1

< p>A major flaw of C language arrays is that it is impossible to know how big the array is when the program is running. This makes it difficult to loop through each item in the array. If you use vector, this task becomes very easy.

The size() method returns the current size of the vector:

for(int i = 0; i < myVar.size(); i++) {

printf("%i", myVar [i]); //Output the i-th item

}

Use the resize method to resize the vector:

myVar.resize(15); //The size of myvar becomes 15

The vector class provides many other useful functions. Click the reference link below to learn more about vector.

String (string)

The string class is used to replace char* to express strings. string provides basic character processing and provides a way for many functions that use char* to still use string. You can use the = and + operators to assign values ??to strings:

string s;

s = "Hello";

s = s + ", world" ;

s starts out as an empty string (size 0). In the second line the value of s changes to "Hello". Then ", world" is added to the end of s, and the value of s becomes "Hello, world".

The method size() returns the length of the string. These codes:

string s = "Hello";

printf("%i", s.size());

will output 5.

You can access a character in a string just like a char array:

string s = "Hello";

printf("%c", s[0]); //Output "H"

s[0] = 'h'; //s becomes "hello"

If a function requires char* Parameters, you can use the c_str() method:

string s = "Hello";

printf("%s", s.c_str()); //Output "Hello"

Answer Example

Look at the following example question:

Our input program will record keyboard input into a sequence of characters. We want to convert the input character sequence into a separate string for later use. Create a method buildstring. This method accepts a vector type parameter. This parameter represents the keyboard input sequence. The buildstring method must return a string merged from this input sequence.

Class: StringBuilder

Method: buildString

Parameters: vector

Return: string

Method signature: string buildString(vector array)

The following answer uses string and vector to solve this problem:

#include

#include

using namespace std;

class StringBuilder {

public:

string buildString(vector array ) {

//Create the string to be returned

string s;

//Loop to read each item in the array

for(int i = 0; i < array.size(); i++) {

s = s + array[i];

}

//Return the created string

return s;

}

};