C++ Programming Labs

Your Task: Create and manipulate an array of integers. Calculate the sum and find the largest element.

Detailed Requirements:
1. Declare and initialize an integer array:
int numbers[5] = {10, 25, 8, 42, 17};
   • int numbers[5] - declares an array that can hold 5 integers
   • = {10, 25, 8, 42, 17} - initializes with these values
   • Array indices start at 0: numbers[0]=10, numbers[1]=25, etc.

2. Print all array elements using a for loop:
for (int i = 0; i < 5; i++) { cout << numbers[i] << " "; }
   • Loop from index 0 to 4 (5 elements)
   • Access each element with numbers[i]

3. Calculate the sum of all elements:
   • Declare int sum = 0; before the loop
   • Inside the loop: sum += numbers[i]; (same as sum = sum + numbers[i])
   • After the loop, print the sum

4. Find the largest element:
   • Declare int largest = numbers[0]; (assume first is largest)
   • Loop through remaining elements
   • If numbers[i] > largest, update: largest = numbers[i];

Key Concepts:
• Arrays are zero-indexed: first element is at index 0
• Array size is fixed at compile time in C++
• Accessing index out of bounds causes undefined behavior (no error, but wrong results)
• Use sizeof(array)/sizeof(array[0]) to get array length dynamically

Expected Output:
Array elements: 10 25 8 42 17 Sum: 102 Largest: 42

Your Task: Work with C++ strings to perform common text operations like concatenation, finding length, and accessing characters.

Detailed Requirements:
1. Declare and initialize two strings:
string firstName = "John";
string lastName = "Doe";
   • Include #include <string> at the top
   • Strings use double quotes, not single quotes

2. Concatenate strings to create full name:
string fullName = firstName + " " + lastName;
   • The + operator joins strings together
   • Add a space " " between first and last name

3. Get and print the string length:
cout << fullName.length() << endl;
   • .length() or .size() returns number of characters
   • "John Doe" has length 8 (space counts!)

4. Access individual characters:
cout << fullName[0] << endl; → prints 'J'
   • Strings are like character arrays
   • Index starts at 0

5. Convert to uppercase (loop through characters):
   • Loop through each character
   • Use toupper() to convert: char upper = toupper(fullName[i]);

Key Concepts:
• C++ string is a class with built-in methods
• Strings are mutable (can be changed after creation)
• Common methods: .length(), .substr(), .find(), .append()
• toupper() and tolower() are in <cctype> header

Expected Output:
First name: John Last name: Doe Full name: John Doe Length: 8 First character: J Uppercase: JOHN DOE

Your Task: Use while loops to implement a number guessing game simulation and calculate factorial.

Detailed Requirements:
1. Create a countdown using while loop:
int count = 5;
while (count > 0) { cout << count << "... "; count--; }
   • While loop continues as long as condition is true
   • count-- decrements count by 1 each iteration
   • Without decrementing, you get an infinite loop!

2. Calculate factorial using while loop:
Factorial of n (written as n!) = n × (n-1) × (n-2) × ... × 1
Example: 5! = 5 × 4 × 3 × 2 × 1 = 120
int n = 5;
int factorial = 1;
int i = 1;
while (i <= n) { factorial *= i; i++; }
   • factorial *= i means factorial = factorial * i

3. Sum numbers until a condition is met:
Add numbers 1, 2, 3, ... until sum exceeds 50
int sum = 0, num = 1;
while (sum <= 50) { sum += num; num++; }
   • Print how many numbers were added
   • Print the final sum

Key Concepts - While vs For:
• Use for when you know exactly how many iterations
• Use while when you don't know how many iterations (condition-based)
• do-while executes at least once, then checks condition

⚠️ Warning: Always ensure your while loop will eventually terminate! If the condition never becomes false, you have an infinite loop.

Expected Output:
Countdown: 5... 4... 3... 2... 1... Liftoff! 5! = 120 Sum of 1 to 10 = 55 (exceeds 50)