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Variables:

int x = 5;
double y = 3.14;
char c = 'A';
bool isTrue = true;

I/O:

#include <iostream>
int a;
std::cin >> a;
std::cout << "The value of a is: " << a << std::endl;`

Control Structure:

if (x > 0) { }
else if { }
 
for (int i = 0; i < 10; ++i) { }
 
int i = 0;
while (i < 10) { ++i }

Functions:

int add(int a, int b) {
return a + b;
}
int main() {
int result = add(2, 3);
std::cout << "Result: " << result << std::endl;
return 0;
} 

Arrays and Vectors:

Array: int arr[5] = {1, 2, 3, 4, 5};

Vector: std::vector<int> vec = {1, 2, 3, 4, 5};

String: std::string str = "Hello, World!";

Vector Methods:

Append (push back): vec.push_back(10);

Pop (removes last): vec.pop_back();

Length/Size: vec.size();

Nullity: if (vec.empty()) { std::cout << "Vec empty" << std::endl;

Clear: vec.clear();

Resize (discards end if needed, or inserting default): vec.resize(5);

At (has bounds checking) / operator[]: vec.at(1) || vec[1];

Front / Back: vec.front() || vec.back();


Pointers and References:

DSA

Set: std::set<int> uniqueNumbers;

Stack: std::stack<int> stack;