数据结构中通过malloc函数创建动态数组失败

####问题发生背景：数据结构顺序栈的初始化失败
####错误信息：S->base=(SElemType)malloc(MAXSIZEsizeof(SElemType));


```c
typedef struct 
{
    int example;
}SElemType;

typedef struct 
{
    SElemType *base;
    SElemType *top;
    int stacksize;
}SqStack;

int main()
{
Status InitStack(SqStack *S);

SqStack *S;
InitStack(S);
printf("%o",S->base);
    
}

Status InitStack(SqStack *S)
{
    S->base=(*SElemType)malloc(MAXSIZE*sizeof(SElemType));
    if(!S->base) exit(OVERFLOW);
    S->top=S->base;
    S->stacksize=MAXSIZE;
    return OK;    
}


详细报错：[Error] expected expression before 'SElemType'

尝试方法：通过调试定位报错语句，最后发现是S->base编译系统无法理解，但S->表示指针所指向的结构体成员变量，语法上是可行的，百思不得其解。


###希望各位掌握相关知识的友友不吝赐教

改动处见注释，供参考：

#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE  50   //修改 
#define OVERFLOW -1   //修改
#define OK 1          //修改
typedef int Status;   //修改
typedef struct{
    int example;
}SElemType;
typedef struct{
    SElemType* base;
    SElemType* top;
    int stacksize;
}SqStack;
int main()
{
    Status InitStack(SqStack * S);
    SqStack* S;
    S = (SqStack*)malloc(sizeof(SqStack)); //修改
    InitStack(S);
    printf("%o", S->base);
    return 0;
}

Status InitStack(SqStack* S)
{
    S->base = (SElemType*)malloc(MAXSIZE * sizeof(SElemType));  //修改
    //S->base = (*SElemType)malloc(MAXSIZE * sizeof(SElemType));
    if (!S->base) 
        exit(OVERFLOW);
    S->top = S->base;
    S->stacksize = MAXSIZE;
    return OK;
}

Status InitStack(SqStack *S); 这个函数声明没移到main函数前面？