C > Data Structures Code Examples

``` Linked list queue example # include <stdio.h> # include <stdlib.h> struct qnode { int data; int prio; struct qnode *next; }; void quein(struct qnode **, struct qnode **, int , int); int quedel(struct qnode **, struct qnode **, int *, int *); int main(void) { int tab[10] = {2, 8, 3, 5, 4, 9, 6, 7, 1, 0}; struct qnode *first = NULL; struct qnode *last = NULL; int val, prio, i; for(i = 0; i < 10; i++) { val = tab[i], prio = i; printf("Inserting: value: %d with priority: %d\n", prio, val); quein(&first, &last, val, prio); } printf("=-=\n"); for(i = 0; i < 11; i++) { val = tab[i], prio = i; if(quedel(&first, &last, &val, &prio) != -1) printf("Deleting: value: %d with priority: %d\n", prio, val); } return 0; } int quedel(struct qnode **first, struct qnode **last, int *prio, int *val) { struct qnode *tmp = NULL; if((NULL == *last) && (*last == *first)) { fprintf(stderr, "Empty queue.....\n"); return -1; } *val = (*first)->data, *prio = (*first)->prio; tmp = *first, *first = (*first)->next; if(*last == tmp) *last = (*last)->next; free(tmp); return 0; } void quein(struct qnode **first, struct qnode **last, int prio, int val) { struct qnode *tmp = NULL; struct qnode *tmp1 = NULL; tmp = malloc(sizeof(struct qnode)); tmp->data = val; tmp->prio = prio; tmp->next = NULL; if(*last == NULL) { *last = tmp; *first = *last; } else { if((*first)->prio < prio) { tmp->next = *first; *first = tmp; } else { if((*last)->prio > prio) { (*last)->next = tmp; *last = tmp; } else { tmp1 = *first; while((tmp1->next)->prio >= prio) { tmp1 = tmp1->next; } tmp->next = tmp1->next; tmp1->next = tmp; } } } return; } ```