bc.c

来自「自己做的常用库和实现的数据结构。public domain.」· C语言 代码 · 共 144 行

/* parsing 1+2*3 */
#include<stdio.h>
#include<stdlib.h>
#include<stddef.h>
#define ADD 1
#define MUL 2
typedef struct opcode {
	char code;
	int pior;	
	size_t sn;
	struct opcode *next;
} OC;
typedef struct oprand {
	int rand;
	size_t sn;
	struct oprand *next;
} OR;
typedef struct bracket {
	char brkt;
	int pior;	
	size_t sn;
	struct bracket *next;
} BK;

int parse(const char *p)
{
	size_t cnt1, cnt2;
	OC *cp;
	OR *rp;
	for(cnt1 = cnt2 = 1; *p; p++) {
		if(isdigit((int)*p)) {
			rp = add_to_oprand_link(*p, cnt);
			cnt1++;
		}
		else switch(*p) {
			case '+':
			case '-':
				cp = add_to_opcode_link(*p, cnt, ADD);
				cnt2++;
				break;
			case '*':
			case '/':
				cp = add_to_opcode_link(*p, cnt, MUL);
				cnt2++;
				break;
		}
	}
	return process(rp, cp);
}

OC *add_to_opcode_link(const char *p, size_t head_flag, int pior_flag)
{
	OC *head, *t, *cp = (OC *)mem_apply(sizeof(OC));
	cp->code = (int)(*p);
	cp->pior = pior_flag;
	cp->sn = head_flag;
	if(head_flag == 1)
		head = t = cp;
	else {
		t->next = cp;
		t = cp;
	}
	return head;
}
OR *add_to_oprand_link(const char *p, size_t head_flag)
{
	OR *head, *t, *rp = (OR *)mem_apply(sizeof(OR));
	rp->rand = (int)(*p);
	rp->sn = head_flag;
	if(head_flag == 1)
		head = t = rp;
	else {
		t->next = rp;
		t = rp;
	}
	return head;
}
int process(OR *rp_head, OC *cp_head)
{
	OR *rp = rp_head;
	OC *cp = cp_head, *t2;
	int t = cp_head->pior;
	if(cp == NULL)
		return rp_head->rand;
	while(cp->next) {
		if(t < cp->next->pior)
			t = cp->next->pior;
		t2 = cp;
		cp = cp->next;
	}
#if (t2->code == '+')
#define OPCODE +
#elif (t2->code == '-')
#define OPCODE -
#elif (t2->code == '*')
#define OPCODE *
#elif (t2->code == '/')
#define OPCODE /
#elif (t2->code == '%')
#define OPCODE %
#endif
	while(rp) {
		if(t == rp->sn) {
			rp->rand  OPCODE= rp->next->rand;
			break;
		}
		rp = rp->next;
	}
	freerp(rp);
	freecp(t2);
}
const void freerp(OR *rp)
{
	OR *t = rp->next;
	rp->next = t->next;
	free(t);
}
const void freecp(OC *cp)
{
	OC *t = cp->next;
	if(cp == cp_head) {
		head = cp->next;
		free(cp);
	}

	cp->next = t->next;
	free(t);
}
const void freenode(OR *rp, OR *rp_head, OC *cp, OC *cp_head)
{
	if(cp) {
		if(cp == cp_head) {
			t = cp->next;
			free(cp);
		}	
	}	
}
int main()
{
	char *a = "1  + 2*3";
	printf("%d", parse);
	return 0;
}