Session 2: Getting Input from Users

Learning Objectives

• Learn to get input from users
• Understand the difference between input and output
• Create interactive programs

Warm-up (5 minutes)

Run your ASCII art program from last session. Does it work? If not, what error messages do you see?

New Concept Introduction (20 minutes)

Input vs Output

• Output: Showing information to the user (we learned cout)
• Input: Getting information from the user (new: cin)

Getting User Input

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#include <iostream>
using namespace std;

int main() {
    string name;  // Create a container to store the user's name
    
    cout << "What's your name? ";
    cin >> name;  // Get input from user
    
    cout << "Hello, " << name << "!" << endl;
    return 0;
}

Key points:

• string name; creates a “variable” to store text
• cin >> gets input from the user
• We can combine text and variables in output using <<

Common Input Types

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string name;     // For text (one word)
int age;         // For whole numbers
double height;   // For decimal numbers

Hands-on Practice (25 minutes)

Exercise 1: Personal Info Collector (10 minutes)

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#include <iostream>
using namespace std;

int main() {
    string name;
    int age;
    
    cout << "Enter your name: ";
    cin >> name;
    
    cout << "Enter your age: ";
    cin >> age;
    
    cout << "Hello " << name << ", you are " << age << " years old!" << endl;
    
    return 0;
}

Exercise 2: Simple Calculator (15 minutes)

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#include <iostream>
using namespace std;

int main() {
    double num1, num2;
    
    cout << "Enter first number: ";
    cin >> num1;
    
    cout << "Enter second number: ";
    cin >> num2;
    
    cout << num1 << " + " << num2 << " = " << num1 + num2 << endl;
    
    return 0;
}

Challenge/Quiz (10 minutes)

Challenge: Mad Libs Generator Create a program that asks for:

• An adjective
• A noun
• A verb
• A place

Then creates a funny sentence using their inputs.

Validation Prompt

```
I'm learning C++ and just completed Session 2. Here's my solution to the Mad Libs Generator challenge:

[PASTE YOUR CODE HERE]

The challenge was: Create a program that asks for an adjective, noun, verb, and place, then creates a funny sentence using their inputs.

Please check if my solution:
1. Compiles correctly
2. Uses cin to get user input
3. Uses cout to display a creative sentence
4. Stores input in appropriately named variables

If there are issues, please explain what's wrong and give me a hint to fix it (don't give me the complete solution).
```

What You Learned

• ✅ How to get input from users with cin
• ✅ Creating variables to store different types of data
• ✅ Combining user input with program output
• ✅ Basic interactive program structure

Next Session Preview

In Session 3, you’ll dive deeper into variables and learn about different data types like integers, decimals, and text!