C Language Interview: Project Experience and Code Examples Sharing

In C language interviews, project experience and practical coding skills are crucial assessment components. This article will help foundational users understand relevant concepts and improve their performance in interviews through some common project cases and corresponding code examples.

1. Professional Background and Project Experience

As a full-stack programmer, I have participated in several projects involving C language, such as:

• Embedded system development
• Operating system kernel module design
• Data structure and algorithm implementation

These experiences have helped me master how to apply C language in practical applications.

2. Data Structure and Algorithm Cases

2.1 Linked List

The linked list is one of the most common data structures and is required in many scenarios. In one of my projects, we created a simple singly linked list to manage dynamic data.

Code Example:

The following is a basic implementation of a singly linked list, including insertion, deletion, and traversal operations.

#include <stdio.h>
#include <stdlib.h>
// Node structure definition
struct Node {
    int data;
    struct Node* next;
};
// Insert node at the end of the linked list
void insert(struct Node** head_ref, int new_data) {
    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
    struct Node* last = *head_ref;
    new_node->data = new_data;
    new_node->next = NULL;
    // If the linked list is empty, new node becomes the head
    if (*head_ref == NULL) {
        *head_ref = new_node;
        return;
    }
    // Otherwise, traverse to the last node and insert the new node
    while (last->next != NULL) {
        last = last->next;
    }
    last->next = new_node;
}
// Delete node with specified value
void deleteNode(struct Node** head_ref, int key) {
    struct Node* temp = *head_ref, *prev;
    // If head node holds the key to be deleted
    if (temp != NULL && temp->data == key) {
        *head_ref = temp->next;
        free(temp);
        return;
    }
    // Search for the key to be deleted, keep track of the previous node
    while (temp != NULL && temp->data != key) {
        prev = temp;
        temp = temp->next;
    }
    // If key was not present in linked list
    if (temp == NULL) return;
    prev->next = temp->next; // Unlink the node from linked list
    free(temp); // Free memory
}
// Print linked list contents
void printList(struct Node* node) {
    while (node != NULL) {
        printf("%d -> ", node->data);
        node = node->next;
    }
    printf("NULL\n");
}
int main() {
    struct Node* head = NULL;
    insert(&head, 1);
    insert(&head, 2);
    insert(&head, 3);
    printf("Current linked list:
");
    printList(head);
    deleteNode(&head, 2);
    printf("Linked list after deletion:
");
    printList(head);
    return 0;
}

Implementation Explanation:

The above code demonstrates how to define a simple singly linked list and provides functions for insertion, deletion, and printing. We first create a <span>Node</span> structure, then use functions to add new elements and delete specified elements based on given values. This process allows beginners to understand pointer operations and dynamic memory allocation, which are core concepts in C language.

2.2 File Operation Example

Another important topic is file handling. In some of my projects, it was necessary to read data from files and process it, which is also a common interview topic.

Code Example:

This is a small example of writing to and reading from a file:

#include <stdio.h>
int main() {
    FILE *fp;
    // Write data to file
    fp = fopen("output.txt", "w");
    if (fp == NULL) {printf("Cannot open file!"); return -1;}
    fprintf(fp, "Hello World!\nThis is a sample file.\n");
    fclose(fp);
    char buffer[255];
    // Read data from file and print it
    fp = fopen("output.txt", "r");
    if (fp == NULL){printf("Cannot open file!"); return -1;}
    while(fgets(buffer, sizeof(buffer), fp)) {
        printf("%s", buffer);
    }
    fclose(fp);
    return 0;
}

Implementation Explanation:

In this example, we first open or create a text file named <span>output.txt</span> in write mode and write a string into it. Then we open the document in read mode and read the content line by line, saving each line’s information in a buffer and outputting it. Mastering file I/O can help you better handle data-related needs and may become a focus during interviews.

Conclusion

Having practical experience is a crucial aspect during C language interviews. For example, through the two cases above, we practiced some basic data structure operations and how to handle different types of input and output. This not only enhances our programming skills but also demonstrates our problem-solving methods. Therefore, when preparing for related interviews, it is essential to summarize your practical experiences, practice more, and maintain an unwavering pursuit of foundational knowledge. I hope this article can be helpful to you.