List Remove

Removing a linked node changes the previous node to skip over it.

list_remove.c

#include <stdio.h>

struct Node {
    int value;
    struct Node *next;
};

int main(void) {
    int removeValue = ;
    struct Node third = {30, 0};
    struct Node second = {20, &third};
    struct Node first = {10, &second};
    struct Node *head = &first;
    struct Node *previous = 0;
    struct Node *current = head;
    int removed = 0;

    while (current != 0 && removed == 0) {
        if (current->value == removeValue) {
            if (previous == 0) {
                head = current->next;
            } else {
                previous->next = current->next;
            }
            removed = 1;
        } else {
            previous = current;
            current = current->next;
        }
    }

    printf("removed=%d head=%d\n", removed, head->value);
    return 0;
}

#include <stdio.h>

struct Node {
    int value;
    struct Node *next;
};

int main(void) {
    int removeValue = ;
    struct Node third = {30, 0};
    struct Node second = {20, &third};
    struct Node first = {10, &second};
    struct Node *head = &first;
    struct Node *previous = 0;
    struct Node *current = head;
    int removed = 0;

    while (current != 0 && removed == 0) {
        if (current->value == removeValue) {
            if (previous == 0) {
                head = current->next;
            } else {
                previous->next = current->next;
            }
            removed = 1;
        } else {
            previous = current;
            current = current->next;
        }
    }

    printf("removed=%d head=%d\n", removed, head->value);
    return 0;
}

#include <stdio.h>

struct Node {
    int value;
    struct Node *next;
};

int main(void) {
    int removeValue = ;
    struct Node third = {30, 0};
    struct Node second = {20, &third};
    struct Node first = {10, &second};
    struct Node *head = &first;
    struct Node *previous = 0;
    struct Node *current = head;
    int removed = 0;

    while (current != 0 && removed == 0) {
        if (current->value == removeValue) {
            if (previous == 0) {
                head = current->next;
            } else {
                previous->next = current->next;
            }
            removed = 1;
        } else {
            previous = current;
            current = current->next;
        }
    }

    printf("removed=%d head=%d\n", removed, head->value);
    return 0;
}

previous pointer The previous node is needed so its link can bypass the removed node.

removed flag A flag records whether the target value was found.