C Code Examples: Calculator, Leap Year, and More

Posted on Feb 21, 2025 in Communication

C Code Examples

1. Calculator

#include <stdio.h>

int main() {
    char operator;
    double num1, num2, result;

    // Input
    printf("Enter an operator (+, -, *, /): ");
    scanf(" %c", &operator);

    printf("Enter two numbers: ");
    scanf("%lf %lf", &num1, &num2);

    // Switch case to perform calculation based on the operator
    switch (operator) {
        case '+':
            result = num1 + num2;
            break;
        case '-':
            result = num1 - num2;
            break;
        case '*':
            result = num1 * num2;
            break;
        case '/':
            if (num2 != 0) {
                result = num1 / num2;
            } else {
                printf("Error: Division by zero is not allowed.\n");
                return 1; // Exit the program with an error code
            }
            break;
        default:
            printf("Error: Invalid operator.\n");
            return 1; // Exit the program with an error code
    }

    // Output the result
    printf("Result: %.2lf %c %.2lf = %.2lf\n", num1, operator, num2, result);

    return 0; // Exit the program successfully
}

2. Leap Year Checker

#include <stdio.h>

int main() {
    int year;

    // Input
    printf("Enter a year: ");
    scanf("%d", &year);

    // Using ternary operator to check for leap year
    (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
        ? printf("%d is a leap year.\n", year)
        : printf("%d is not a leap year.\n", year);

    return 0; // Exit the program successfully
}

3. Second Largest Element in Array

#include <stdio.h>

int main() {
    int n;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];
    printf("Enter %d elements:\n", n);
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    // Find the second largest element
    int largest, secondLargest;

    if (n < 2) {
        printf("Array should have at least two elements.\n");
        return 1; // Exit the program with an error code
    }

    // Initialize the largest and secondLargest with the first two elements
    if (arr[0] > arr[1]) {
        largest = arr[0];
        secondLargest = arr[1];
    } else {
        largest = arr[1];
        secondLargest = arr[0];
    }

    for (int i = 2; i < n; i++) {
        if (arr[i] > largest) {
            secondLargest = largest;
            largest = arr[i];
        } else if (arr[i] > secondLargest && arr[i] != largest) {
            secondLargest = arr[i];
        }
    }

    printf("The second largest element is: %d\n", secondLargest);

    return 0; // Exit the program successfully
}

4. Matrix Operations

#include <stdio.h>

int main() {
    int rows, cols;

    // Input: Size of the matrices
    printf("Enter the number of rows: ");
    scanf("%d", &rows);

    printf("Enter the number of columns: ");
    scanf("%d", &cols);

    // Input: Matrix A
    int matrixA[rows][cols];
    printf("Enter elements for Matrix A:\n");
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            printf("Enter element at position (%d, %d): ", i + 1, j + 1);
            scanf("%d", &matrixA[i][j]);
        }
    }

    // Input: Matrix B
    int matrixB[rows][cols];
    printf("Enter elements for Matrix B:\n");
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            printf("Enter element at position (%d, %d): ", i + 1, j + 1);
            scanf("%d", &matrixB[i][j]);
        }
    }

    // Subtract matrices and calculate transpose of the resultant matrix
    int resultMatrix[rows][cols];
    int transposeMatrix[cols][rows];

    // Subtract matrices
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            resultMatrix[i][j] = matrixA[i][j] - matrixB[i][j];
        }
    }

    // Calculate transpose of the resultant matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            transposeMatrix[j][i] = resultMatrix[i][j];
        }
    }

    // Display the resultant matrix
    printf("\nResultant Matrix (A - B):\n");
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            printf("%d\t", resultMatrix[i][j]);
        }
        printf("\n");
    }

    // Display the transpose of the resultant matrix
    printf("\nTranspose of the Resultant Matrix:\n");
    for (int i = 0; i < cols; i++) {
        for (int j = 0; j < rows; j++) {
            printf("%d\t", transposeMatrix[i][j]);
        }
        printf("\n");
    }

    return 0; // Exit the program successfully
}

5. Bubble Sort

#include <stdio.h>

// Function to perform bubble sort on an array
void bubbleSort(int arr[], int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            // Swap if the element found is greater than the next element
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n;

    // Input: Size of the array
    printf("Enter the number of elements: ");
    scanf("%d", &n);

    int arr[n];

    // Input: Array elements
    printf("Enter %d elements:\n", n);
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    // Perform bubble sort
    bubbleSort(arr, n);

    // Output: Display the sorted array
    printf("Sorted array using Bubble Sort:\n");
    for (int i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }

    return 0; // Exit the program successfully
}