c - 在c中为全局变量赋值会导致错误

Question

我有以下代码:

struct TreeNode {
     int val;
     struct TreeNode *left;
     struct TreeNode *right;
};


 #define MAXSIZE 1024

 typedef struct stack{
     struct TreeNode volum[MAXSIZE];
     int top;
 }STACK;

 STACK st;
 st.top = -1;

/* other function definitions such as pop() and push() */

但是当我编译它时，它给出了错误第 18 行:在“.”标记之前预期有“=”、“,”、“;”、“asm”或“__attribute__”。其中第 18 行是 st.top=-1;

所以这里我需要初始化堆栈，即将顶部设置为-1。我也尝试在结构内部执行此操作: int top=-1; 但遇到了相同的错误。我想知道正确的做法是什么。提前致谢。

Answer 1

你可以试试

typedef struct stack {
    int top;
    struct TreeNode volum[MAXSIZE];
} STACK;

STACK st = { -1 }; // top has to be the first member of the struct