54 lines
1.1 KiB
C
54 lines
1.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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typedef struct c { int d; struct c *n, *p; } *C;
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C l = NULL;
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C new_c(int v) {
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C t = (C)malloc(sizeof(struct c));
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t->d = v; t->n = t->p = NULL; return t;
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}
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void insert_beg(int v) {
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C t = new_c(v);
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if (!l) { l = t; l->n = l->p = l; }
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else {
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t->n = l->n;
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l->n->p = t;
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t->p = l;
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l->n = t;
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}
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}
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void del_end() {
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if (!l) printf("List is empty");
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else {
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C p = l->p;
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p->n = l->n;
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l->n->p = p;
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free(l);
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l = p;
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}
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}
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void traverse() {
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if (!l) return;
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C c = l->n;
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do { printf("%d ", c->d); c = c->n; } while (c != l->n);
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printf("\n");
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}
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int main() {
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char cont = 'y'; int ch;
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while (cont == 'y') {
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printf("1. Insert at beginning\n2. Delete at end\n3. Traverse\n");
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scanf("%d", &ch);
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if (ch == 1) { int v; scanf("%d", &v); insert_beg(v); }
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else if (ch == 2) { del_end(); printf("Element deleted\n"); }
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else if (ch == 3) { traverse(); }
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printf("Continue? (y/n)\n");
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fflush(stdin);
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scanf(" %c", &cont);
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}
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return 0;
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}
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