Basics: Array & Dynamic Array

Introduction to Array

	#include <iostream>
	int main() {
	// 1. Initialize
	int a0[5];
	int a1[5] = {1, 2, 3}; // other element will be set as the default value
	// 2. Get Length
	int size = sizeof(a1) / sizeof(*a1);
	cout << "The size of a1 is: " << size << endl;
	// 3. Access Element
	cout << "The first element is: " << a1[0] << endl;
	// 4. Iterate all Elements
	cout << "[Version 1] The contents of a1 are:";
	for (int i = 0; i < size; ++i) {
	cout << " " << a1[i];
	}
	cout << endl;
	cout << "[Version 2] The contents of a1 are:";
	for (int& item: a1) {
	cout << " " << item;
	}
	cout << endl;
	// 5. Modify Element
	a1[0] = 4;
	// 6. Sort
	sort(a1, a1 + size);
	}
	/*
	Finished in 3 ms
	The size of a1 is: 5
	The first element is: 1
	[Version 1] The contents of a1 are: 1 2 3 0 0
	[Version 2] The contents of a1 are: 1 2 3 0 0
	*/

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Introduction to Dynamic Array

	#include <iostream>
	int main() {
	// 1. initialize
	vector<int> v0;
	vector<int> v1(5, 0);
	// 2. make a copy
	vector<int> v2(v1.begin(), v1.end());
	vector<int> v3(v2);
	// 2. cast an array to a vector
	int a[5] = {0, 1, 2, 3, 4};
	vector<int> v4(a, *(&a + 1));
	// 3. get length
	cout << "The size of v4 is: " << v4.size() << endl;
	// 4. access element
	cout << "The first element in v4 is: " << v4[0] << endl;
	// 5. iterate the vector
	cout << "[Version 1] The contents of v4 are:";
	for (int i = 0; i < v4.size(); ++i) {
	cout << " " << v4[i];
	}
	cout << endl;
	cout << "[Version 2] The contents of v4 are:";
	for (int& item : v4) {
	cout << " " << item;
	}
	cout << endl;
	cout << "[Version 3] The contents of v4 are:";
	for (auto item = v4.begin(); item != v4.end(); ++item) {
	cout << " " << *item;
	}
	cout << endl;
	// 6. modify element
	v4[0] = 5;
	// 7. sort
	sort(v4.begin(), v4.end());
	// 8. add new element at the end of the vector
	v4.push_back(-1);
	// 9. delete the last element
	v4.pop_back();
	}
	/*
	The size of v4 is: 5
	The first element in v4 is: 0
	[Version 1] The contents of v4 are: 0 1 2 3 4
	[Version 2] The contents of v4 are: 0 1 2 3 4
	[Version 3] The contents of v4 are: 0 1 2 3 4
	*/

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Introduction to 2D Array

	#include <iostream>
	template <size_t n, size_t m>
	void printArray(int (&a)[n][m]) {
	for (int i = 0; i < n; ++i) {
	for (int j = 0; j < m; ++j) {
	cout << a[i][j] << " ";
	}
	cout << endl;
	}
	}
	int main() {
	cout << "Example I:" << endl;
	int a[2][5];
	printArray(a);
	cout << "Example II:" << endl;
	int b[2][5] = {{1, 2, 3}};
	printArray(b);
	cout << "Example III:"<< endl;
	int c[][5] = {1, 2, 3, 4, 5, 6, 7};
	printArray(c);
	cout << "Example IV:" << endl;
	int d[][5] = {{1, 2, 3, 4}, {5, 6}, {7}};
	printArray(d);
	}
	/*
	Example I:
	-1511528224 32563 -1511527904 32563 -1511524608
	32563 2 0 54005184 0
	Example II:
	1 2 3 0 0
	0 0 0 0 0
	Example III:
	1 2 3 4 5
	6 7 0 0 0
	Example IV:
	1 2 3 4 0
	5 6 0 0 0
	7 0 0 0 0
	*/

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