Exchanging Variable Values

Directly assigning one variible to another overwrites the original data, preventing recovery of the initial value. To successfully interchange contents between two storage locations, a temporary buffer is necessary.

Consider this implementation using standard integer types:

#include <iostream>
using namespace std;

int main() {
    int valOne = 15;
    int valTwo = 25;
    
    cout << "Before swap: One=" << valOne << ", Two=" << valTwo << endl;
    
    // Use a third variable to hold intermediate data
    int tempStorage = valOne;
    valOne = valTwo;
    valTwo = tempStorage;
    
    cout << "After swap: One=" << valOne << ", Two=" << valTwo << endl;
    return 0;
}

Commenting Syntax

Comments allow developers to documetn logic without impacting the execution flow.

Single-Line Comments

Start with //. The compiler ignores all text following this marker on the same line.

int count = 0; // Initialize counter

Multi-Line Comments

Enclose text blocks between /* and */ to ignore multiple lines at once.

/*
   Explanation for complex logic
   spanning several lines
*/

Practice Exercises

Exercise 1: Output Input

Acccept a single integer from standard input and display it.

#include <iostream>
using namespace std;

int main() {
    int inputNumber;
    cin >> inputNumber;
    cout << inputNumber;
    return 0;
}

Exercise 2: Selective Printing

Read three distinct integers and output only the middle value.

#include <iostream>
using namespace std;

int main() {
    int first, second, third;
    cin >> first >> second >> third;
    cout << second;
    return 0;
}

Exercise 3: Sequence Generation

Input a base number and print the value plus zero, then plus an increment, repeated twice.

#include <iostream>
using namespace std;

int main() {
    int baseValue;
    int increment = 25;
    
    cin >> baseValue;
    
    cout << baseValue << " ";
    cout << baseValue + increment << " ";
    cout << baseValue + increment + increment;
    
    return 0;
}