Q18: Implement a C++ program that converts temperatures between Celsius and Fahrenheit. Ask the user for the temperature and the unit, then perform the conversion based on the input. Hint:
(Temperature in degrees Fahrenheit (°F) = (Temperature in degrees Celsius (°C) * 9/5) + 32)

#include <iostream>
using namespace std;
int main() {
float c, f;
cout << " value ";
cin >> c;
f = ( c * 9/5 ) + 32;
cout << " in F the temp is :" << f <<endl;
    return 0;
}

Q19: Create a C++ program that takes two integers as input and checks whether the first number is divisible by the second one. Provide appropriate messages based on the result.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    int num1, num2; 
 
    cout << "Enter the first number: "; 
    cin >> num1; 
 
    cout << "Enter the second number: "; 
    cin >> num2; 
 
    if (num2 != 0)  
 { 
        if (num1 % num2 == 0)  
  { 
            cout << num1 << " is divisible by " << num2 << endl; 
        }  
  else  
  { 
            cout << num1 << " is not divisible by " << num2 << endl; 
        } 
    }  
 else  
 { 
        cout << "Error: Division by zero is not allowed." << endl; 
    } 
 
    return 0; 
}

Q20: Write a C++ program that takes three numbers as input and determines the largest among them using conditional statements

#include <iostream> 
using namespace std; 
 
int main() { 
    double num1, num2, num3; 
 
    cout << "Enter num1 : "; 
    cin >> num1; 
 
    cout << "Enter num2 : "; 
    cin >> num2; 
 
    cout << "Enter num3 : "; 
    cin >> num3; 
 
    if (num1 >= num2 && num1 >= num3) { 
        cout << "The largest number is : " << num1 << endl; 
    }  
 else if (num2 >= num1 && num2 >= num3)  
 { 
        cout << "The largest number is : " << num2 << endl; 
    }  
 else  
 { 
        cout << "The largest number is : " << num3 << endl; 
    } 
 
    return 0; 
}

Q21: Create a C++ program that takes three angles as input and classifies the triangle based on the angle values (acute, obtuse, or right-angled). determines the largest among them using conditional statements

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    int angle1, angle2, angle3; 
 
    cout << "Enter the first angle: "; 
    cin >> angle1; 
 
    cout << "Enter the second angle: "; 
    cin >> angle2; 
 
    cout << "Enter the third angle: "; 
    cin >> angle3; 
 
    if (angle1 + angle2 + angle3 == 180)  
 { 
        if (angle1 < 90 && angle2 < 90 && angle3 < 90)  
  { 
            cout << "The triangle is acute-angled." << endl; 
        }  
  else if (angle1 == 90 || angle2 == 90 || angle3 == 90)  
  { 
            cout << "The triangle is right-angled." << endl; 
        } 
   else  
  { 
            cout << "The triangle is obtuse-angled." << endl; 
        } 
    }  
 else  
 { 
        cout << "Invalid input: The angles do not form a triangle." << endl; 
    } 
 
    return 0; 
}

Q22: Write a C++ program that calculates the total cost after applying a discount based on the purchase amount. For example, provide a 10% discount if the purchase amount is above $100.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
int purchaseamount, discount, totalcost;
cout<<" enter the purchaseamount: ";
cin>>purchaseamount;
if ( purchaseamount > 100)
{
discount = 0.10 * purchaseamount;
}
else
{
discount = 0;
}
totalcost = purchaseamount - discount;

cout<< "Discount applied: $"<<discount<<endl;
cout<< "Total cost after discount: $"<<totalcost<<endl;

return 0; 
}

Q23: C++ code to calculate the factorial of any entered number.

#include <iostream> 
using namespace std; 
 
int main() 
{ 
    int a , fac; 
    cout << "enter the number (a) : "; 
    cin >> a; 
    fac = 1; 
    for ( int i =1; i <= a ; i++) 
    { 
        fac = fac * i; 
    } 
    cout << "the fac of the entered number is : "<<fac<<endl;
    
    return 0; 
}

Q24: C++ code to calculate the power of any entered number (the base and exponent should be entered by user).

#include <iostream> 
using namespace std; 
 
int main() 
 { 
    float base, exponent, result; 
 
    cout << "Enter the base: "; 
    cin >> base; 
 
    cout << "Enter the exponent: "; 
    cin >> exponent; 
 
    result = 1; 
     
    for(int i=0;i<exponent;i++) 
    { 
     result*=base; 
 } 
 
    cout << base << " raised to the power of " << exponent << " is: " << result << endl; 
 
    return 0; 
}

Q25: Write a program that calculates and prints the sum of the even integers from 2 to user defined limit. Use a do-while loop that asks the user whether the program should be terminated or not.

#include <iostream>
using namespace std;
int main()
{
 char input;
 do {
    int num, sum_even = 0;
    cout << "enter the number : ";
    cin >> num;

    for (int b = 2; b <= num; b += 2)
    {
        sum_even += b;
    }
    cout << " sum of even numbers from 2 to "<<num<<" is :"<< sum_even<< endl;
    cout << " Do you want to terminate the program or not? ( y/n):" ;
    cin >> input;
 }
     while (input != 'y');
     
     return 0;
 }

Q26: Write a C++ program to print the sequence of numbers (101, 111, 112 … 130), except number 107 and 125.

#include <iostream> 
using namespace std; 
int main() 
{
for ( int i = 101; i <= 130; i++ )
{
if ( i!=107 && i!=125)
cout << i << endl;
}
return 0;
}

Q27: Write a program that calculates and prints the product of odd integers from 1 to user defined limit. Use a do-while loop that asks the user whether the program should be terminated or not.

#include <iostream>
using namespace std;
int main()
{
 char input;
 do {
    int num, product_odd = 1;
    cout << "enter the value of m : ";
    cin >> num;
    for (int b = 1; b <= num; b += 2)
    {
        product_odd *= b;
    }
    cout << " product of odd numbers from 1 to"<<num<<":"<< product_odd<< endl;
    cout << " Do you want to terminate the program or not? ( y/n):" ;
    cin >> input;
 }
     while (input != 'y');
     return 0;
 }

Q28: Write a program which takes PIN number of the user as input and then verifies his pin. If pin is verified the program shall display “pin verified” and “Welcome”; otherwise, the program shall give user another chance. After 4 wrong attempts, the program shall display “Limit expired” and then exit.
Use for loops to implement the logic.
Note: 5 random PIN numbers can be assumed and fed into the program with which input pin is matched.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    const int MAX_ATTEMPTS = 4; 
    int pinAttempts = 0; 
    int enteredPIN; 
    int validPINs[] = {1234, 5678, 9876, 5432, 1111}; 
 
    for (int i = 0; i < MAX_ATTEMPTS; ++i)  
 { 
        cout << "Enter your PIN: "; 
        cin >> enteredPIN; 
 
        bool pinVerified = false; 
 
        for (int j = 0; j < 5; ++j)  
  { 
            if (enteredPIN == validPINs[j])  
   { 
                pinVerified = true; 
                break; 
            } 
        } 
 
        if (pinVerified)  
  { 
            cout << "PIN verified. Welcome!" << endl; 
            break; 
        } else  
  { 
            cout << "Incorrect PIN. Please try again." << endl; 
            ++pinAttempts; 
 
            if (pinAttempts == MAX_ATTEMPTS)  
   { 
                cout << "Limit expired. Exiting program." << endl; 
                break; 
            } 
        } 
    } 
 
    return 0; 
}

Q28: Write a program which takes PIN number of the user as input and then verifies his pin.
If pin is verified the program shall display “pin verified” and “Welcome”; otherwise, the program shall give user another chance. After 4 wrong attempts, the program shall display “Limit expired” and then exit.
Use for loops to implement the logic.
Note: 5 random PIN numbers can be assumed and fed into the program with which input pin is matched.

#include <iostream>
using namespace std;

int main() {
    // Assume 5 random PIN numbers
    int pinNumbers[5] = {1234, 5678, 9876, 4321, 7890};
    int userPIN;
    int attempts = 0;

    // Loop for maximum 4 attempts
    for (int i = 0; i < 4; ++i) {
        cout << "Enter your PIN number: ";
        cin >> userPIN;

        // Check if the entered PIN matches any of the stored PINs
        bool pinVerified = false;
        for (int j = 0; j < 5; ++j) {
            if (userPIN == pinNumbers[j]) {
                pinVerified = true;
                break;
            }
        }

        if (pinVerified) {
            cout << "PIN verified" << endl;
            cout << "Welcome" << endl;
            break;
        } else {
            cout << "Invalid PIN. Please try again." << endl;
            attempts++;
        }
    }

    // If the user exceeds 4 attempts
    if (attempts == 4) {
        cout << "Limit expired" << endl;
    }

    return 0;
}

Q29: Write a C++ program to calculate the summation of the following sequence for nth terms.
𝑆𝑢𝑚 = 1/1 + 2/4 + 3/9 + ....

#include <iostream> 
using namespace std; 
 
int main()  
{
int n;
double sum = 0;
cout<<" enter the value of n : ";
cin>>n;
for( int i = 1; i <= n; i++)
{
sum += float (i) / (i*i);
}
cout<<" the summation the following sequence for "<<n<<" is : "<<sum<<endl;
return 0; 
}

Q30: C++ code to find the summation of the following series.
Sum = a + a^2 + a^3 + ... + a^n

#include <iostream>
using namespace std;

int main() {
    int a, n;
    int sum = 0;

    cout << "Enter the value of 'a': ";
    cin >> a;

    cout << "Enter the value of 'n': ";
    cin >> n;

    // Calculating the summation of the series
    for (int i = 1; i <= n; ++i) {
        int term = 1;
        for (int j = 1; j <= i; ++j) {
            term *= a;
        }
        sum += term;
    }
    cout << "The summation of the series is: " << sum << endl;

    return 0;
}

Q31: C++ code to find the summation of the following series for nth terms.
𝑆𝑢𝑚 = 1/a^1 + 2/a^2 + 3/a^3 + ....

#include <iostream>
using namespace std;

int main() {
    int a, n;
    float sum = 0.0;
    float power_of_a = 1.0;

    cout << "Enter the value of 'a': ";
    cin >> a;

    cout << "Enter the value of 'n': ";
    cin >> n;

    // Calculating the summation of the series
    for (int i = 1; i <= n; ++i) {
        power_of_a *= a; // Update power_of_a by multiplying it by a
        sum += float(i) / power_of_a;
    }

    cout << "The summation of the series up to the " << n << "th term is: " << sum << endl;

    return 0;
}

Q32: C++ code to find the summation of the following series.
Sum = 1 + 2! + 3! + ⋯ + n!

#include <iostream>
using namespace std;

int main() {
    int n;
    int sum = 0;
    int factorial = 1;

    cout << "Enter the value of 'n': ";
    cin >> n;

    for (int i = 1; i <= n; ++i) {
        factorial *= i;
        sum += factorial; 
    }

    cout << "The summation of the series is: " << sum << endl;

    return 0;
}

Q33: Grades in the programming lab are classified according to letters A case of Excellent, B case of Well done, C case of done, D case of Pass and F case of Try again.
Write C++ code to implement this logic using Switch statement.

#include <iostream>
using namespace std;
int main ()
{
char grade ;
cout << " take one from this ( A , B, C, D, F) ";
cin >> grade;
switch(grade)
{
case 'A' :
cout << "Excellent!" << endl;
break;
case 'B' :
cout << "Well done" << endl;
break;
case 'C' :
cout << "done" << endl;
break;
case 'D' :
cout << "You passed" << endl;
break;
case 'F' :
cout << "Better try again" << endl;
break;
default :
cout << "Invalid grade" << endl;
}
cout << "Your grade is " << grade << endl;
return 0;
}

Q34: Create a C++ program that takes five integers as input and determines whether their product is positive or negative.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    int num1, num2, num3, num4, num5; 
    int product; 
 
    cout << "Enter five integers: "; 
    cin >> num1 >> num2 >> num3 >> num4 >> num5; 
 
    product = num1 * num2 * num3 * num4 * num5; 
 
    if (product > 0)  
 { 
        cout << "The product is positive." << endl; 
    }  
 else if (product < 0)  
 { 
        cout << "The product is negative." << endl; 
    } 
  else  
 { 
        cout << "The product is zero." << endl; 
    } 
 
    return 0; 
}

Q35: Write a C++ program that takes a day number (1-7) as input and prints the corresponding day of the week.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    int daynumber; 
 
    cout << " enter the day ( 1 -7 ) : "; 
    cin >> daynumber;
    switch (daynumber)
    {
    case 1:
    cout<< " sunday "<<endl;
    break;
    case 2:
    cout<< " monday "<<endl;
    break;
    case 3:
    cout<< " tuseday "<<endl;
    break;
    case 4:
    cout<< " wednesday "<<endl;
    break;
    case 5:
    cout<< " thursday "<<endl;
    break;
    case 6:
    cout<< " friday "<<endl;
    break;
    case 7:
    cout<< " saturday "<<endl;
    break;
    default:
    cout<<" not defined/true "<<endl;
    }
    
    return 0; 
}

Q36: Write a C++ program that determines if a person is eligible to vote based on their age. Consider the legal voting age as 18.

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    int age;
    cout<<" enter your age : ";
    cin>>age;
    if ( age >= 18)
    {
    cout<< " you are eligible to vote "<<endl;
    }
    else
    {
    cout<< " you are not eligible to vote "<<endl;
    }
    return 0; 
}

Q37: Write C++ program takes an input of a person first name and uses a switch statement to output the corresponding person's age (consider three persons)

#include <iostream> 
using namespace std; 
 
int main()  
{ 
    char firstName; 
 
    cout << "Enter a person's first initial (A/B/C): "; 
    cin >> firstName; 
 
    switch (firstName)  
 { 
        case 'A': 
        case 'a': 
            cout << "The age of person with first initial A is: 25" << endl; 
            break; 
        case 'B': 
        case 'b': 
            cout << "The age of person with first initial B is: 30" << endl; 
            break; 
        case 'C': 
        case 'c': 
            cout << "The age of person with first initial C is: 35" << endl; 
            break; 
        default: 
            cout << "Unknown person" << endl; 
    } 
 
    return 0; 
}