تحديات for في لغة ++C: حلول مبتكرة لأسئلة متنوعة

 Ex1: Write C++ program to read two integer numbers then print "multiple" or "not" if one number is a multiple to another number. using for loop.

Sol//

#include <iostream>

using namespace std;

int main() {
    int num1, num2;

    cout << "Enter the first integer: ";
    cin >> num1;

    cout << "Enter the second integer: ";
    cin >> num2;

    // Check for division by zero first
    if (num2 == 0) {
        cout << "Error: Division by zero." << endl;
        return 1; // Indicate error
    }

    // Simulate divisibility check using a for loop (inefficient)
    bool isMultiple = true;
    for (int i = 1; i * num2 <= num1; i++) {
        if (num1 == i * num2) {
            isMultiple = true;
            break; // Exit loop if a multiple is found
        } else {
            isMultiple = false;
        }
    }

    if (isMultiple) {
        cout << num1 << " is a multiple of " << num2 << endl;
    } else {
        cout << num1 << " is not a multiple of " << num2 << endl;
    }

    return 0;
}

Ex2: Write C++ program to read integer number and print the equivalent string. e.a: 0 ->zero 1-> one 2-> Two .

using for loop.

Sol//

#include <iostream>
#include <string>

using namespace std;

int main() {
    int num;
    string numberStrings[] = {"zero", "one", "two", "three", "four", "five",
                             "six", "seven", "eight", "nine"};

    cout << "Enter an integer between 0 and 9: ";
    cin >> num;

    // Input validation (optional)
    if (num < 0 || num > 9) {
        cout << "Invalid input. Please enter a number between 0 and 9." << endl;
        return 1; // Indicate error
    }

    // Simulate string lookup using a for loop (inefficient)
    bool found = false;
    for (int i = 0; i < 10; i++) {
        if (i == num) {
            cout << numberStrings[i] << endl;
            found = true;
            break;
        }
    }

    if (!found) {
        cout << "An unexpected error occurred." << endl; // Should never reach here with proper input validation
    }

    return 0;
}

Ex3: Write C++ program to read a score of student and print the estimation to refer it. e.a: 100 - 90 7 Exultant 89 - 80 ➔ Very good 79- 70 ➔ Good 69 - 60 7 Middle 59 - 50 ➔ Accept 49 - 0 ➔ Fail . using for loop.

Sol//

#include <iostream>

using namespace std;

int main() {
    int score;

    cout << "Enter the student's score (0-100): ";
    cin >> score;

    // Input validation (optional)
    if (score < 0 || score > 100) {
        cout << "Invalid score. Please enter a value between 0 and 100." << endl;
        return 1; // Indicate error
    }

    // Simulate estimation using a for loop (inefficient)
    string estimations[] = {"Exultant", "Very good", "Good", "Middle", "Accept", "Fail"};
    int thresholds[] = {100, 90, 80, 70, 60, 50, 0}; // Assuming descending order

    for (int i = 0; i < 6; i++) {
        if (score >= thresholds[i]) {
            cout << "Estimation: " << estimations[i] << endl;
            break;
        }
    }

    return 0;
}

Ex4: Write C++ program to read an integer number and check if it is positive or negative, even or odd, and write a suitable messages in each case. using for loop.

Sol//

#include <iostream>

using namespace std;

int main() {
    int num;

    cout << "Enter an integer: ";
    cin >> num;

    // Simulate separate checks using a for loop (inefficient)
    bool isPositive = false;
    bool isEven = false;

    // Check for positive/negative (inefficient)
    for (int i = 1; i <= num; i++) {
        if (num > 0) {
            isPositive = true;
            break;
        }
    }

    // Check for even/odd (inefficient)
    for (int i = 1; i <= abs(num); i++) { // Use abs() for efficient modulus check
        if (i % 2 == 0) {
            isEven = true;
            break;
        }
    }

    cout << num << " is ";
    if (isPositive) {
        cout << "positive";
    } else {
        cout << "negative";
    }

    cout << " and ";
    if (isEven) {
        cout << "even." << endl;
    } else {
        cout << "odd." << endl;
    }

    return 0;
}

Ex5: Write C++ program to reads a character and print if it is digit (0 .. 9), capital letter (A,B, ... ,Z), small letter (a, b, ... ,z), special character ( +, !, @, #, ~ {, >, ... ).  using for loop.

Sol//

#include <iostream>
#include <cctype> // For character classification functions

using namespace std;

int main() {
    char ch;

    cout << "Enter a character: ";
    cin >> ch;

    // Simulate classification using a for loop (inefficient)
    bool isDigit = false;
    bool isUppercase = false;
    bool isLowercase = false;
    bool isSpecial = false;

    for (int i = 0; i <= 127; i++) { // Iterate through all ASCII characters (less efficient)
        if (ch == '0' + i && i <= 9) {
            isDigit = true;
            break;
        } else if (ch == 'A' + i && i <= 25) {
            isUppercase = true;
            break;
        } else if (ch == 'a' + i && i <= 25) {
            isLowercase = true;
            break;
        }
    }

    isSpecial = !isDigit && !isUppercase && !isLowercase; // Special character if not digit, uppercase, or lowercase

    cout << ch << " is ";
    if (isDigit) {
        cout << "a digit." << endl;
    } else if (isUppercase) {
        cout << "an uppercase letter." << endl;
    } else if (isLowercase) {
        cout << "a lowercase letter." << endl;
    } else if (isSpecial) {
        cout << "a special character." << endl;
    } else {
        cout << "an unexpected character." << endl; // Shouldn't happen with valid input
    }

    return 0;
}

Ex6- Write C++ program  to find the following series: using for loop.

Sol//

#include <iostream>
#include <cmath> // for pow function

using namespace std;

int main() {
    int n = 10; // Number of terms (replace with 10 for the given series)
    double sum = 0;

    for (int i = 1; i <= n; i++) {
        sum += pow(2, i); // Calculate 2 raised to the power of i and add to the sum
    }

    cout << "The sum of the series 2^1 + 2^2 + ... + 2^" << n << " is: " << sum << endl;

    return 0;
}

Ex7- Write C++ program  to find the following series: using for loop.

Sol//

#include <iostream>

using namespace std;

int main() {
    double z = 4.0; // Initialize with first term (4)
    int sign = 1;    // Start with positive sign

    for (int denominator = 3; denominator <= 13; denominator += 2) {
        z += sign * (4.0 / denominator);
        sign *= -1; // Alternate signs
    }

    cout << "The sum of the series z = 4 - 4/3 + 4/5 - 4/7 + ... + 4/13 is: " << z << endl;

    return 0;
}

Ex8: Write C++ program to inverse an integer number. For example: 7 65432 ➔ 234567 .using for loop?

Sol//

#include <iostream>
#include <limits> // for numeric_limits

using namespace std;

int main() {
    long long int num; // Use long long to handle larger numbers

    cout << "Enter an integer: ";
    cin >> num;

    // Check for negative input and handle overflow
    if (num < 0) {
        cout << "Error: Negative input is not allowed." << endl;
        return 1; // Indicate error
    } else if (num > numeric_limits<long long int>::max() / 10) {
        cout << "Error: Number too large for inversion." << endl;
        return 1; // Indicate error
    }

    long long int reversed = 0;
    int digit;

    for (; num != 0; num /= 10) {
        digit = num % 10;
        reversed = reversed * 10 + digit;
    }

    cout << "The reversed number is: " << reversed << endl;

    return 0;
}

Ex9: Write C++ program that utilize looping and the escape sequence \t to print the following table of value:

 N  , 1 0 * N ,100 * N ,1000 * N 

1        10        100        1000

2        20        200        2000

3        30        300        3000

4        40        400        4000

Hint\t to print six spaces. using for loop.

Sol//

#include <iostream>

using namespace std;

int main() {
    int N;

    cout << "Enter a value for N: ";
    cin >> N;

    cout << "N\t10 * N\t100 * N\t1000 * N\n"; // Header row with labels

    // Loop for rows (1 to 4)
    for (int i = 1; i <= 4; ++i) {
        cout << i << "\t" << 10 * i << "\t" << 100 * i << "\t" << 1000 * i << endl;
    }

    return 0;
}

Ex10 : Write C++ program to find e from the following series: e = 1 + (1 /1 !) + (1 /2!) + (1 /3!) + ... + (1 /n!) . using for loop.

Sol//

#include <iostream>
#include <cmath> // for std::factorial

using namespace std;

int main() {
    int n;
    double e = 1.0; // Initialize with 1

    cout << "Enter the number of terms (higher n for better accuracy): ";
    cin >> n;

    // Input validation (optional)
    if (n <= 0) {
        cout << "Error: Please enter a positive number of terms." << endl;
        return 1;
    }

    double factorial = 1.0;
    for (int i = 1; i <= n; ++i) {
        factorial *= i; // Calculate factorial for each term
        e += 1.0 / factorial; // Add the term to the approximation
    }

    cout << "Approximation of e with " << n << " terms: " << e << endl;

    return 0;
}

Ex11: Write C++ program to find e from the following series: e = 1 + x + (x^2 / 2!) + (x^3 / 3!) + ... (x^a / a!) . using for loop.

Sol//

#include <iostream>
#include <cmath> // for std::factorial

using namespace std;

int main() {
    double x, e = 1.0; // Initialize with 1
    int a;

    cout << "Enter the value of x: ";
    cin >> x;

    cout << "Enter the power a (positive integer): ";
    cin >> a;

    // Input validation (optional)
    if (a <= 0) {
        cout << "Error: Please enter a positive power a." << endl;
        return 1;
    }

    double term = 1.0, power = x; // Initialize term and power

    for (int i = 1; i <= a; ++i) {
        term *= power / i; // Calculate next term (x^i / i!)
        e += term;         // Add the term to the approximation
        power *= x;        // Update power for next term
    }

    cout << "Approximation of e for x = " << x << " and a = " << a << " terms: " << e << endl;

    return 0;
}

Ex 12: Write C++ program to print the following searies: 

1. Sum=1+2^2 +4^2 + ... +n^2 

2. Sum=1-3^x+5^x-... +n^x 

3. Sum=1 + 1/1! +2/2!+3/3! + ... +n/n!   where n!=1 *2*3* ... *n ..using for loop.

Sol//

#include <iostream>
#include <cmath> // for std::pow

using namespace std;

int main() {
    int n;
    double sum1 = 0, sum2 = 0, sum3 = 0;
    double x; // for series 2

    cout << "Enter the number of terms (n): ";
    cin >> n;

    // Input validation for n (positive integer)
    if (n <= 0) {
        cout << "Error: Please enter a positive number of terms." << endl;
        return 1;
    }

    cout << "Enter the value of x for series 2 (optional, enter 0 for default 1): ";
    cin >> x;
    if (x == 0) {
        x = 1; // Set default value for x
    }

    // Calculate and print the series
    for (int i = 1; i <= n; ++i) {
        sum1 += pow(i, 2);  // Series 1: Sum of squares (1^2 + 2^2 + ... + n^2)
        sum2 += pow(-1, i + 1) * pow(x, i); // Series 2: Alternating series (1 - 3x + 5x^2 - ...)
        double factorial = 1.0;
        for (int j = 1; j <= i; ++j) {
            factorial *= j;
        }
        sum3 += i / factorial; // Series 3: Sum of factorials (1 + 1/1! + 2/2! + ...)
    }

    cout << "Series 1 (Sum of squares): " << sum1 << endl;
    cout << "Series 2 (Alternating series): " << sum2 << endl;
    cout << "Series 3 (Sum of factorials): " << sum3 << endl;

    return 0;
}