Control in C++

Insert Notes here for learning C++ Control Flow

IF Else Conditions

Code For using the Or Operator:

#include <iostream>
#include <string>

using namespace std;

int main () 
{
    string answer = "Devin";
    int age_answer = 24;

    string guess;
    cout << "Guess my name!: ";
    cin >> guess;

    int age_guess;
    cout << "Guess my Age: ";
    cin >> age_guess;


    if (guess == answer || age_guess == age_answer )  
    {

        cout << "Correct, you guessed it right!\n";
    }


    else
    {
        cout << "You entered both the age and name incorrectly\n! ";
    }

    return 0;

}

Code for Using Not Equal Operator:

#include <iostream>
#include <string>

using namespace std;


int main () 
{
    string answer = "Devin";

    string guess;

    cout << "Guess my name!: ";
    cin >> guess;


    if ( (guess != answer) )  
    {

        cout << "You got the Wrong Name Sir!\n";
        cout << "The name you entered was: " << guess << endl;
    }

    else
    {
        cout << "You entered the Right name Devin!\n";
    }
    

    return 0;
}

Code for using the Not Operator:

#include <iostream>
#include <string>

using namespace std;


int main () 
{
    string answer = "Devin";

    string guess;

    cout << "Guess my name!: ";
    cin >> guess;


    if ( !(guess == answer) )  
    {

        cout << "You got the Wrong Name Sir!\n";
        cout << "The name you entered was: " << guess << endl;
    }

    else
    {
        cout << "You entered the Right name Devin!\n";
    }
    

    return 0;
}

Loops

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For Loops

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For Loop Code:

#include <iostream>

using namespace std;

int main () 
{
    for(int i =0; i < 10; i++ )
    {
        cout << i << endl;
    }
    return 0;
}

Display name multiple times using a for loop:

#include <iostream>

using namespace std;

int main() {
    for (int i = 1; i <= 5; ++i) {
        cout <<  "My name is Devin!!! " << endl;
    }
    return 0;
}

We can also do a Range Based for loop.

#include <iostream>

using namespace std;

int main() {

    int number_array[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

    for (int n : number_array) {
        cout << n << " ";
    }

    return 0;
}

While Loop

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While Loop Code:

#include <iostream>

using namespace std;

int main () 
{
    int i = 0; // initization

    while (i < 10) // Condtion
    {
        cout << i << endl;

        i ++; // Update
    }

    return 0;
}

While Loop Factorial Example:

#include <iostream>

using namespace std;

int main () 
{
    int fact = 5;
    int factorial = fact; // 5 * 4 * 3 * 2 * 1
    int i = factorial - 1;

    while( i > 1)
    {
        factorial *= i;
        i-- ;

    }

    cout << "Factorial of " << fact << " is: " << factorial << endl;

}

Here is an example of a while loop that will sum up numbers given, until 0 is entered in:

#include <iostream>
using namespace std;

int main() {
    int number;
    int sum = 0;

    cout << "Enter a number: ";
    cin >> number;

    while (number != 0) {

        sum += number;

        // take input again if the number is not 0
        cout << "Enter a number: ";
        cin >> number;
    }

    // display the sum
    cout << "\nThe sum is " << sum << endl;
    
    return 0;
}

Do While Loop

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Do While Loop Code for Guessing the Correct Password:

#include <iostream>

using namespace std;

int main () 
{
    string  password = "Hellotacos123";
    string guess;
    do 
    {
        cout << "Guess the password: ";
        cin >> guess;

    } while(guess != password);

    cout << "Exited out the 'Do While Loop' because you entered the Correct Password" << endl;

}

Can we do this “do while” loop using a regualr while loop?

#include <iostream>

using namespace std;

int main () 
{
    string  password = "Hellotacos123";
    string guess;
    cout << "Guess the Password: ";
    cin >> guess;
    while(guess != password)
    {
        cout << "Guess the Password: ";
        cin >> guess;
    }

    cout << "Exited out the 'Do While Loop' because you entered the Correct Password" << endl;

}

Break and Continue Keywords

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Break out of Code Example:

#include <iostream>
#include <string>

using namespace std;

int main () 
{
string sentence = "Hello my name is Devin";

for (int i = 0; i < sentence.size(); i++ )
{
    cout << sentence[i] << endl;
    if (sentence[i] == 'o')
    {
        cout << "Found o!\n ";
        break;
    }
}
cout << "Done!\n";
}

Continue Keyword to skip example:

#include <iostream>
#include <string>

using namespace std;

int main () 
{
string sentence = "Hello my name is Devin";

for (int i = 0; i < sentence.size(); i++ )
{
    if (sentence[i] == 'o')
    {
        continue;
    }
    cout << sentence[i] << endl;
    
}
cout << "Done!\n";
}

Using Continue in a for loop while printing the numbers 1 to 10, and skipping current iteration and updating the expression once i = 5

#include <iostream>


int main() {
    for (int i = 1; i <= 10; i++) {
        if (i == 5) {
            continue;
        }

        std::cout << i << std::endl;
    }

    return 0;
}

Output

Another Continue Example using it with a while loop!

Conditional Operator Examples

Conditional Operator Code:

#include <iostream>
#include <string>

using namespace std;

int main () 
{
int answer = 11;
cout << "Guess the number: ";
int guess;

cin >> guess;  

int points = guess == answer ? 10 : 0;

cout << points << endl;
    
}

Can also do this for the Conditional Operator:

#include <iostream>
#include <string>

using namespace std;

int main () 
{
int answer = 11;
cout << "Guess the number: ";
int guess;
cin >> guess;  

guess == answer ? cout << "Good Job\n" : cout << "bad job\n";
    
}