Variables, Types and Input

C++ types are explicit and fixed. Choosing the right one matters for correctness and memory use.

Basic Types

int for whole numbers, double for decimals, char for one character, bool for true or false and std::string for text.

#include <string>

int age = 16;
double price = 2500.50;
char grade = 'A';
bool active = true;
std::string name = "Amina";

Reading Input

std::cin reads from the keyboard. For a full line with spaces, use std::getline.

#include <iostream>
#include <string>

int main() {
    int age;
    std::cout << "Age: ";
    std::cin >> age;

    std::cin.ignore();

    std::string name;
    std::cout << "Full name: ";
    std::getline(std::cin, name);

    std::cout << name << " is " << age << " years old.\n";
    return 0;
}

Formatting

Use std::fixed and std::setprecision for consistent decimal places. Include <iomanip>.

#include <iomanip>
#include <iostream>

std::cout << std::fixed << std::setprecision(2) << 2687.5 << "\n";

Practice

1. Read two numbers and print their sum.
2. Read a full name with spaces.
3. Print a price with two decimal places.

Hands-on exercise

Write a program that reads a name, age and average score, then prints them in a clean format with the score to one decimal place.

Recap

C++ types are explicit. Use cin for tokens, getline for full lines and iomanip for formatted output.