/*展示结构体标签和结构体变量*/
#include <stdio.h>

/*at 结构体标签*/
typedef struct at_tag {
    char name[9];
    char gender[2];
    int age;
};
/*st 结构体变量*/
typedef struct {
    char name[9];
    char gender[2];
    int age;
}st_variate;

void test(void)
{
    struct at_tag tag= {
        "徐达开",
        "M",
        24
    };
    printf("标签结构体：\n");
    printf("%s %s %d\n", tag.name, tag.gender, tag.age);

    st_variate variate= {
        "孙尚香",
        "W",
        1000
    };
    printf("结构体变量：\n");
    printf("%s %s %d\n", variate.name, variate.gender, variate.age);
}
int main()
{
    test();
    return 0;
}

//计算3+5，怎么通过结构体指针变量关联add函数，以及通过结构体指针调用add函数输出结果？
#if 1
#include <stdio.h>
#include <stdlib.h>

typedef struct
{
    int (*func)(int, int);
    int a;
    int b;

}func_t;

int add(int a, int b) { return a + b; }

int main()
{
    func_t* func1 = (func_t*)malloc(sizeof(func_t));
    //计算3+5，怎么通过结构体指针变量关联add函数，以及通过结构体指针调用add函数输出结果？
    /*func1->func = add;
    int result = func1->func(3, 5);*/
    func1[0].func = add;
    func1[0].a = 3;
    func1[0].b = 5;
    int result = func1[0].func(func1[0].a, func1[0].b);
    printf("3+5=%d\n", result);
    return 0;
}
#endif

/*输入整数为小数点有瑕疵(解决)
* 相较比较完美的代码
*/
#if 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
typedef struct  st{
    int (*fun)(int, int);
    char ari[3];
};
int my_Add(int a, int b) { return a + b; }
int my_Sub(int a, int b) { return a - b; }
int my_Mul(int a, int b) { return a * b; }
int my_Div(int a, int b) { return a / b; }
//st* func1 = NULL;
int main()
{
    //st * func1 = (st*)malloc(sizeof(st) * 4);
    struct st *func1 = malloc( sizeof(struct st));
    int a = 0, b = 0;
    int scanfResult;
    char extreChar;
    //double a_input, b_input;
    char choice[10];
    
    func1[0].fun = my_Add;
    strcpy(func1[0].ari, "add");
    func1[1].fun = my_Sub;
    strcpy(func1[1].ari, "sub");
    func1[2].fun = my_Mul;
    strcpy(func1[2].ari, "mul");
    func1[3].fun = my_Div;
    strcpy(func1[3].ari, "div");
    
    while (1) {
        printf("choice arithmetic:add\tsub\tmul\tdiv\n");
        scanf("%s", choice);
     /*   if (choice < 1 || choice >4)
        {
            printf("input invalid\n");
            continue;
        }*/
        int choice_flag = -1;
        for (int i = 0; i < 4; ++i) {
            if (strcmp(choice, func1[i].ari) == 0) {
                choice_flag = i;
                break;
            }
        }
        if (choice_flag == -1) {
            printf("arithmetic input invaild\n");
            continue;
        }

        printf("inpout two integer\n");
        scanfResult = scanf("%d %d", &a, &b);
        if (scanfResult != 2) {
            printf("Invalid input. Please enter two integers.\n");
            //清楚输入缓冲区中的额外字符
            while ((extreChar = getchar()) !='\n' && extreChar != EOF);
            continue;
        }

        int result = func1[choice_flag].fun(a, b);
        printf("%s:%d a=%d b=%d\n", func1[choice_flag].ari, result, a, b);
    }
    free(func1);
    return 0;
}
#endif