#include <stdio.h>
#include <stdlib.h>
typedef char EXPRESS[40]
typedef struct fraction {
    int num;
    int den;
} FRACTION;
typedef struct s_item {
    FRACTION value;
    EXPRESS expr;
    int map;
    struct s_item*next;
} ITEM,*PITEM;

#include <stdio.h>
#include <stdlib.h>
typedef char EXPRESS[40];
typedef struct fraction {
    int num;
    int den;
} FRACTION;
typedef struct s_item {
    FRACTION value;
    EXPRESS expr;
    int map;
    struct s_item*next;
} ITEM,*PITEM;

谢谢谢谢。太粗心了，一直以为是定义出错了