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 发表于 2022-11-1 19:15:21
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| 像这样,写一个容器来存储这些表达式
 
 复制代码sh-5.1$ ls
list.c        list.h        main.c
sh-5.1$ cat main.c
#include "list.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
typedef struct {
    int a, b;
    char op;
    int result;
} exp_t;
int calc(int a, char op, int b) {
    switch(op) {
        case '+': return a + b;
        case '-': return a - b;
        case '*': return a * b;
        case '/': return a / b;
    }
    return 0;
}
void output(const list_t *list, size_t index) {
    if(index >= list_size(list)) return;
    output(list, index + 1);
    exp_t e; list_get(list, index, &e, sizeof(e));
    printf("%d %c %d = %d\n", e.a, e.op, e.b, e.result);
}
int main(void) {
    srand(time(NULL));
    list_t *list = list_init();
    for(size_t i = 0; i < 10; ++i) {
        exp_t e;
        e.a = rand() % 100;
        e.b = rand() % 100;
        e.a = rand() % 2 ? e.a : -e.a;
        e.b = rand() % 2 ? e.b : -e.b;
        char op[] = {'+', '-', '*', '/'};
        e.op = op[rand() % 4];
        e.op = e.op == '/' && e.b == 0 ? op[0] : e.op;
        e.result = calc(e.a, e.op, e.b);
        list_append(list, &e, sizeof(e));
    }
    output(list, 0);
    list_deinit(list);
    return 0;
}
sh-5.1$ cat list.h
#ifndef _LIST_H_
#define _LIST_H_
#include <stddef.h>
#include <stdbool.h>
struct list_node_tag {
    void *data; size_t size;
    struct list_node_tag *next;
};
typedef struct {
    struct list_node_tag *head;
    size_t size;
} list_t;
list_t *list_init(void);
void list_deinit(list_t *list);
bool list_clean(list_t *list);
bool list_insert(list_t *list, size_t index, const void *data, size_t size);
bool list_delete(list_t *list, size_t index);
bool list_get(const list_t *list, size_t index, void *data, size_t size);
bool list_set(list_t *list, size_t index, const void *data, size_t size);
bool list_append(list_t *list, const void *data, size_t size);
size_t list_size(const list_t *list);
bool list_empty(const list_t *list);
#endif
sh-5.1$ cat list.c
#include "list.h"
#include <stdlib.h>
#include <memory.h>
list_t *list_init(void) {
    list_t *list = malloc(sizeof(*list));
    if(!list) return NULL;
    list->head = NULL;
    list->size = 0;
    return list;
}
void list_deinit(list_t *list) {
    if(!list) return;
    list_clean(list);
    free(list);
}
bool list_clean(list_t *list) {
    if(!list) return false;
    while(!list_empty(list)) list_delete(list, 0);
    return true;
}
bool list_insert(list_t *list, size_t index, const void *data, size_t size) {
    if(!list) return false;
    if(list_size(list) < index) return false;
    if(!data) return false;
    struct list_node_tag **current = &list->head;
    while(index--) current = &(*current)->next;
    struct list_node_tag *node = malloc(sizeof(*node));
    if(!node) return false;
    node->data = malloc(size);
    if(!node->data) {free(node); return false;}
    memcpy(node->data, data, size);
    node->size = size;
    node->next = *current;
    *current = node;
    ++list->size;
    return true;
}
bool list_delete(list_t *list, size_t index) {
    if(!list) return false;
    if(list_size(list) <= index) return false;
    struct list_node_tag **current = &list->head;
    while(index--) current = &(*current)->next;
    struct list_node_tag *temp = *current;
    *current = temp->next;
    free(temp->data); free(temp);
    --list->size;
    return true;
}
bool list_get(const list_t *list, size_t index, void *data, size_t size) {
    if(!list) return false;
    if(list_size(list) <= index) return false;
    if(!data) return false;
    struct list_node_tag *const *current = &list->head;
    while(index--) current = &(*current)->next;
    struct list_node_tag *temp = *current;
    if(temp->size > size) return false;
    memcpy(data, temp->data, temp->size);
    return true;
}
bool list_set(list_t *list, size_t index, const void *data, size_t size) {
    bool res = list_delete(list, index);
    return res ? list_insert(list, index, data, size) : res;
}
bool list_append(list_t *list, const void *data, size_t size) {
    if(!list) return false;
    return list_insert(list, list_size(list), data, size);
}
size_t list_size(const list_t *list) {
    if(!list) return 0;
    return list->size;
}
bool list_empty(const list_t *list) {
    if(!list) return true;
    return list_size(list) == 0;
}
sh-5.1$ gcc -g -Wall -o main main.c list.c
sh-5.1$ ls
list.c        list.h        main  main.c
sh-5.1$ ./main
23 - -77 = 100
37 * -58 = -2146
94 * 19 = 1786
7 - -24 = 31
51 * 99 = 5049
68 + -48 = 20
-95 * -80 = 7600
-5 + -33 = -38
15 * 18 = 270
-93 - 95 = -188
sh-5.1$
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