basic operations of c++ containers

containers.cpp

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <map>

static int cmp(int a, int b) {
	return a > b;
}

void testVector() {
	std::vector<int> v1; // declare a vector
	for(int i=0; i<10; i++)
		v1.push_back(i); // append to tail
	v1.pop_back(); // remove the last element
	v1[0] = 100; // alter value (by random access)
	v1.insert(v1.begin() + 1, 10); // insert somewhere a value
	v1.erase(v1.begin()+1); // erase element at the position
	v1.erase(v1.begin(), v1.end()-2); // erase elements in an interval
	v1.resize(5); // resize vector(add 0 for default)
	std::reverse(v1.begin(), v1.end()); // reverse vector
	// traverse by random access
	for (unsigned int i = 0; i < v1.size(); i++) {
		std::cout << v1[i] << "\t";
	}
	std::cout<<std::endl;
	// sort
	std::sort(v1.begin(), v1.end());
	// sort with a specified compare function
	std::sort(v1.begin(), v1.end(), cmp);
	// traverse by a iterator
	for (std::vector<int>::iterator iter = v1.begin(); iter != v1.end();
			iter++) {
		std::cout << *iter << "\t";
	}
	std::cout<<std::endl;
}

void testSet(){
	std::set<int> s;
	// insert elements, duplicated element will not insert twice
	for(int i=0; i<10; i++)
		s.insert(i), s.insert(i);

	s.erase(2); // erase a key
	for(int i=0; i<5; i++){
		// search element
		std::set<int>::iterator f = s.find(i); // search key
		if(f!=s.end()) // if not found, iterator will go to the last
			std::cout << "    found " << *f << std::endl;
		else
			std::cout << "not found " << i << std::endl;
	}
	for(std::set<int>::iterator iter = s.begin(); iter!=s.end(); iter++){
		std::cout << *iter << " ";
	}
	std::cout << std::endl;
	s.clear();
}

void testMap(){
	std::map<int, int> tree_mp;
	for(int key=1; key<10; key++)
		tree_mp[key] = key*10; // add key-values

	tree_mp.erase(2); // remove by key

	// traverse key-values
	std::map<int, int>::iterator iter = tree_mp.begin();
	while(iter != tree_mp.end()){
		std::cout << iter->first << " : " << iter->second << std::endl;
		iter ++;
	}

	for(int key=0; key<5; key++){
		std::map<int, int>::iterator f = tree_mp.find(key); // search key
		if(f!=tree_mp.end()) //if not found, iterator will go to the last
			std::cout << "found " << f->first << " : " << f->second << std::endl;
		else
			std::cout << "not found " << f->first << " : " << f->second << std::endl;
	}

}


int main() {
	testVector();
	testSet();
	testMap();
}