C++ Syntax Cheatsheet

Everything in one place

Use this chapter as a quick reference once you've worked through the rest of the course. It collects every core construct of C++ into runnable, copy-pasteable snippets you can scan whenever you forget the exact syntax.

Hello world & variables

```cpp
#include <iostream>

int main() { std::cout << "Hello, World!\n"; return 0; }

int age = 25; std::string name = "Aman"; bool isStudent = true; std::cout << name << " " << age << "\n"; ```

Data types & operators

```cpp
int n = 42;
double d = 3.14;
char c = 'A';
bool b = true;
std::string s = "hello";
std::vector<int> v = {1, 2, 3};

int a = 10, b = 3; std::cout << a + b << " " << a % b << "\n"; std::cout << (a > b && b < 5) << "\n"; ```

Conditionals & loops

```cpp
int score = 72;
if (score >= 90) std::cout << "A";
else if (score >= 60) std::cout << "Pass";
else std::cout << "Fail";

for (int i = 0; i < 5; i++) std::cout << i << "\n";

std::vector v = {1,2,3}; for (int n : v) std::cout << n << "\n"; ```

Functions & arrays

```cpp
int add(int a, int b) {
    return a + b;
}

int main() { std::cout << add(2, 3); }

#include std::vector nums = {10, 20, 30}; nums.push_back(40); for (int n : nums) std::cout << n << "\n"; ```

Strings & objects

```cpp
std::string name = "PlayLearn";
std::cout << name.size() << "\n";
std::cout << name.substr(0, 4) << "\n";

class User { public: std::string name; int age; User(std::string n, int a) : name(n), age(a) {} std::string greet() { return "Hi " + name; } };

User u("Aman", 20); std::cout << u.greet(); ```

Errors, modules & I/O

```cpp
try {
    throw std::runtime_error("Something broke");
} catch (const std::exception &e) {
    std::cerr << e.what() << "\n";
}

// math.h int add(int a, int b);

// math.cpp int add(int a, int b) { return a + b; }

// main.cpp #include "math.h" int main() { return add(2, 3); }

std::string name; std::cout << "Your name? "; std::getline(std::cin, name); std::cout << "Hello, " << name; ```

How to use this page

Bookmark it. When you start a new project, open this cheatsheet alongside your editor and use it as a syntax lookup. Once a construct becomes second nature you'll stop needing the reference for it — and that's exactly when you know you've mastered that part of C++.