#include <iostream>
using namespace std;
bool isPrime(int num) {
    if (num < 2) return false;
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) return false;
    }
    return true;
}

void findPrimes(int n) {
    cout << "Prime Numbers: ";
    for (int i = 1; i <= n; i++) {
        if (isPrime(i))
            cout << i << " ";
    }
    cout << endl;
}

int main() {
    int n;
    cout << "Enter value of n: ";
    cin >> n;
    findPrimes(n);
    return 0;
}

Sample I/O:Enter value of n: 20
Prime Numbers: 2 3 5 7 11 13 17 19

🔗 Run Online: Prime Number between Range

#include <stdio.h>
int main() {
    int m, n, i, j;

    // Input matrix dimensions
    printf("Enter the number of rows (m): ");
    scanf("%d", &m);
    printf("Enter the number of columns (n): ");
    scanf("%d", &n);

    int matrix[m][n];

    // Input matrix elements
    printf("Enter the elements of the matrix row-wise:\n");
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            scanf("%d", &matrix[i][j]);
        }
    }

    // Calculate and print row sums
    printf("\nMatrix with Row Sums:\n");
    for (i = 0; i < m; i++) {
        int rowSum = 0;
        for (j = 0; j < n; j++) {
            printf("%d ", matrix[i][j]);
            rowSum += matrix[i][j];
        }
        printf("%d\n", rowSum); // Row sum
    }

    // Calculate and print column sums
    printf("\nColumn Sums:\n");
    for (j = 0; j < n; j++) {
        int colSum = 0;
        for (i = 0; i < m; i++) {
            colSum += matrix[i][j];
        }
        printf("%d ", colSum);
    }

    return 0;
}

Sample I/O:Enter the number of rows (m): 3
Enter the number of columns (n): 4
Enter the elements of the matrix row-wise:
1  3  4  2
2  4  5  3
3  2  2  5
Output:
Matrix with Row Sums:
1  3  4  2  10
2  4  5  3  14
3  2  2  5  12

Column Sums:
6  9  11  10

🔗Sum of rows and columns of a m X n matrix.

#include <iostream>
using namespace std;
int main() {
    int i, num, n, count;
    cout << "Enter the range: "; 
    cin >> n;
    cout << "The prime numbers in between the range 1 to " << n << " are: ";

    for (num = 1; num <= n; num++) {
        count = 0;
        for (i = 2; i <= num / 2; i++) {
            if (num % i == 0) {
                count++;
                break;
            }
        }
        if (count == 0 && num != 1)
            cout << num << " ";
    }

    return 0;
}

Sample I/O:
Enter the range: 50
The prime numbers in between the range 1 to 50 are: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 

=== Code Execution Successful ===

🔗 Run Online: Prime number between range

#include <iostream>
using namespace std;
int main() {
    int size1, size2;
    // Taking input size of first array
    cout << "Enter size of first array: "; 
    cin >> size1;
    int arr1[size1];
    cout << "Enter elements of first array:\n";
    for (int i = 0; i < size1; i++) {
        cin >> arr1[i];
    }
    // Taking input size of second array
    cout << "Enter size of second array: ";
    cin >> size2;
    int arr2[size2];
    cout << "Enter elements of second array:\n";
    for (int i = 0; i < size2; i++) {
        cin >> arr2[i];
    }
    // To store common elements
    int commonElements[size1 < size2 ? size1 : size2];
    int count = 0;
    // Check each element in arr1 against arr2
    for (int i = 0; i < size1; i++) {
        bool found = false;
        for (int j = 0; j < size2; j++) {
            if (arr1[i] == arr2[j]) {
                found = true;
                break;
            }
        }
        if (found) {
            // Check for duplicates
            bool alreadyExists = false;
            for (int k = 0; k < count; k++) {
                if (commonElements[k] == arr1[i]) {
                    alreadyExists = true;
                    break;
                }
            }
            if (!alreadyExists) {
                commonElements[count] = arr1[i];
                count++;
            }
        }
    }
    // Print common elements
    cout << "Common elements: ";
    for (int i = 0; i < count; i++) {
        cout << commonElements[i] << " ";
    }
    cout << endl;
    // Print total count
    cout << "Total number of common elements: " << count << endl;
    return 0;
}

Sample I/O:
Enter size of first array: 5
Enter elements of first array: 0 20 30 40 50
Enter size of second array: 6
Enter elements of second array: 10 2 20 30 60 90
Common elements: 20 30 
Total number of common elements: 2

=== Code Execution Successful ===

🔗 Run Online: Print Common Elements Between Two Arrays

#include <iostream>
using namespace std;
int main() {
    int i, j, n, p, q;
    cout << "Input number of rows: "; 
    cin >> n;
    for (i = 1; i <= n; i++) {
        if (i % 2 == 0) {
            p = 1;
            q = 0;
        } else {
            p = 0;
            q = 1;
        }
        for (j = 1; j <= i; j++) {
            if (j % 2 == 0)
                cout << p;
            else
                cout << q;
        }
        cout << endl;
    }
    return 0;
}

Sample I/O:
Input number of rows: 6
1
01
101
0101
10101
010101
=== Code Execution Successful ===

🔗 Run Online: Floyd’s Triangle

#include <iostream>
using namespace std;

int main() {
    int n, i, sum = 0, term = 1, nextTerm;
    cout << "Enter the value of n: "; 
    cin >> n;
    cout << "The series is: ";
    for (i = 1; i <= n; i++) {
        cout << term << " ";
        sum += term;
        nextTerm = term + i;
        term = nextTerm;
    }

    cout << "\nThe sum of the series is: " << sum << endl;
    return 0;
}

Sample I/O:
Enter the value of n: 10
The series is: 1 2 4 7 11 16 22 29 37 46 
The sum of the series is: 175

=== Code Execution Successful ===

🔗 Run Code: Sum of series: 1+2+4+7+11+…+N

C++ Code Execution Explanation

Step-by-Step Execution

Initial values:
a = 5, b = 18, c = 27

Step 1: a = b++ + ++c;
• b++ → use 18, then b = 19
• ++c → increment first → c = 28, use 28
⇒ a = 18 + 28 = 46
Now: a = 46, b = 19, c = 28

Step 2: b = a++ - c--;
• a++ → use 46, then a = 47
• c-- → use 28, then c = 27
⇒ b = 46 – 28 = 18
Now: a = 47, b = 18, c = 27

Step 3: c = a++ + b--;
• a++ → use 47, then a = 48
• b-- → use 18, then b = 17
⇒ c = 47 + 18 = 65
Now: a = 48, b = 17, c = 65

Final Output

a = 48
b = 17
c = 65

#include <stdio.h>
void printDivisibleBy3(int arr[], int size) {
    for (int i = 0; i < size; i++) {
        if (arr[i] % 3 == 0) {
            printf("%d\n", arr[i]);
        }
    }
}
int main() {
    int size;
    printf("Enter the number of elements: ");
    scanf("%d", &size);

    int numbers[size];  // Variable Length Array (VLA)
    printf("Enter %d numbers:\n", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &numbers[i]);
    }
    printf("Numbers divisible by 3:\n");
    printDivisibleBy3(numbers, size);
    return 0;
}

Sample I/O:
Enter the number of elements: 6
Enter 6 numbers:
5 6 9 12 8 11
Numbers divisible by 3:
6
9
12
=== Code Execution Successful ===

🔗Run Online: Divisible by 3 in the array.

#include <stdio.h>
int main() {
int num, sum = 0, digit;
printf("Enter a 5-digit number: ");
scanf("%d", &num);
while (num != 0) {
digit = num % 10;   // get last digit
        sum = sum + digit; // add digit to sum
        num = num / 10;// remove last digit
    }
printf("Sum of digits = %d\n", sum);
return 0;
}

🔗Run Online: Sum of Digit

#include <stdio.h>

// Function to find the missing number
int findMissing(int arr[], int size) {
    int total = (size * (size + 1)) / 2;   // Sum of numbers from 1 to size
    int sum = 0;

    for(int i = 0; i < size; i++) {
        sum += arr[i];
    }

    return total - sum;   // Missing number
}

int main() {
    int arr[10] = {1, 2, 3, 4, 5, 0, 7, 8, 9, 10};
    int missing;

    missing = findMissing(arr, 10);

    // Replace zero with missing number
    for(int i = 0; i < 10; i++) {
        if(arr[i] == 0) {
            arr[i] = missing;
        }
    }

    printf("Restored Array:\n");
    for(int i = 0; i < 10; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

#include <stdio.h>

// Recursive function to find nth Fibonacci number
int fibonacci(int n) {
    if (n == 0)
        return 0;
    else if (n == 1)
        return 1;
    else
        return fibonacci(n - 1) + fibonacci(n - 2);
}

int main() {
    int n;

    printf("Enter value of n: ");
    scanf("%d", &n);

    printf("The %dth Fibonacci number is: %d\n", n, fibonacci(n));

    return 0;
}