Lately, I’ve been using LeetCode to prepare for an internship and was surprised by how much the C++ standard has evolved since I studied it as an undergraduate. It’s fascinating to revisit C++ and explore the new features and improvements.
Data Structures #
Vector #
vector is a sequence container in the C++ Standard Library that provides dynamic array functionality.
#include <vector>
using namespace std;
vector<int> numbers = {1, 2, 3};
// as function parameter
vector<int> twoSum(vector<int>& nums, int target) {};
// access element
cout << "The first element of the vector is:" << numbers[0] << endl;
// add element
numbers.push_back(1);
numbers.push_back("hello");
// remove element
numbers.pop_back();
// used in loops
for (int num : numbers) {};
// size
int size = numbers.size();
// check if it's empty
bool isEmpty = numbers.empty();
// sum
int totalSum = accumulate(numbers.begin(), numbers.end(), 0);
String #
#include <string>
using namespace std;
string str = "I love engineering."
// length
int len = str.length();
// find substr
bool isSubstr = str.find("love")
// extract a substring
string substr = str.substr(pos, len)
// check if it's empty
bool isEmpty = str.empty();
Unordered_map #
unordered_map is a type of associative container in the C++ Standard Library used to store key-value pairs.
#include <unordered_map>
using namespace std;
unordered_map<char, int> myMap = {
{'I', 1},
{'V', 5}
};
// Checking if a Key Exists:
if (myMap.find(3) != myMap.end()) {
// Key 3 exists
}