函数空间分配问题

[bo]问题：Program has received a signal-name="SIGSEGV",signal-meaning="Segmentation fault" at Push({name="S",value="0x0"},{name="e",value="35"}), file C:\Program\MinGWStudio\Templates\EvaluateExpression\EvaluateExpression.c:66[/bo]

程序：
#include<stdio.h>
#include<stdlib.h>

#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10
#define TRUE 1
#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define OVERFLOW -2

typedef int Status;
typedef struct{
    int *base;//存储空间初始分配量
    int *top;//栈顶指针
    int stacksize;//当前已分配的存储空间，以元素为单位
}SqStack;

SqStack *OPTR,*OPND;//全局变量OPTR和OPND分别为运算符栈和运算数栈

//以下InitStack()，Push ()，Pop()，Emptys()及GetTop()函数均借鉴数据结构（C语言版）教材
Status InitStack(SqStack *S){
    //构造一个空栈S
    S=(SqStack *)malloc(sizeof(SqStack));
    S->base=(int *)malloc(STACK_INIT_SIZE*sizeof(int));
    if(!S->base)exit(OVERFLOW);//存储分配失败
    S->top=S->base;
    S->stacksize=STACK_INIT_SIZE;
    return OK;
}//InitStackz

Status Push (SqStack *S,int e){
    //插入元素e为新的栈顶元素
    if(S->top-S->base>=S->stacksize){//栈满，追加存储空间
        S->base=(int *)realloc(S->base,(S->stacksize+STACKINCREMENT)*sizeof(int));
    if(!S->base)exit(OVERFLOW);//存储分配失败
    S->top=S->base+S->stacksize;
    S->stacksize+=STACKINCREMENT;
    }//if
    *S->top++=e;
    return OK;
}//Push

Status Pop(SqStack *S,int e){
    //若栈不空，则删除S的栈顶元素，用e返回其值
    if(S->top==S->base)return ERROR;
    e=*--S->top;
    return (e);
}//Pop

Status Emptys(SqStack *S){
    //若栈空，返回TRUE，否则返回FALSE
    if(S->top==S->base)
        return TRUE;
    else
        return FALSE;
}

Status GetTop(SqStack *S){
    //若栈不空，则用e返回S的栈顶元素
    int e;
    if(S->top==S->base)return ERROR;
    e=*(S->top-1);
    return(e);
}//GetTop

char Precede (char ch1,char ch2){
    //构造算符间的优先关系，优先关系借鉴数据结构（C语言版）教材
    if(ch1=='+'||ch1=='-')
    {
        if(ch2=='+'||ch2=='-'||ch2==')'||ch2=='#')return('>');
        else if(ch2=='*'||ch2=='/'||ch2=='(')return('<');
    }
    else if(ch1=='*'||ch1=='/')
    {
        if(ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2==')'||ch2=='#')return('>');
        else if(ch2=='(')return('<');
    }
    else if(ch1=='(')
    {
        if(ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2=='(')return('<');
        else if(ch2==')')return('=');
    }
    else if(ch1==')')
    {
        if(ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2==')'||ch2=='#')return('>');
        //else if()return('=')
    }
    else if(ch1=='#')
    {
        if(ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2=='(')return('<');
        else if(ch2=='#')return('=');
    }
    else if(!((ch1=='+'||ch1=='-'||ch1=='*'||ch1=='/'||ch1=='('||ch1==')'||ch1=='#')&&(ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2=='('||ch2==')'||ch2=='#')))
        //非算符退出
        return ERROR;
}

Status Operate(int a,char theta,int b){
    //四则运算
    if(theta=='+')return (a+b);
    else if(theta=='-')return (a-b);
    else if(theta=='*')return (a*b);
    else if(theta=='/')return (a/b);
}//Operate
Status In(char c){
    //判断c是否是运算符，如果是返回OK，否则返回ERROR。
    if(c=='+'||c=='-'||c=='*'||c=='/'||c=='('||c==')'||c=='#')    
        return OK;
    else
        return ERROR;
}//In
Status EvaluateExpression(){
    //算术表达式求值的算符优先算法。
    int a,b,c,x;
    char theta;
    InitStack(OPTR);Push(OPTR,'#');
    InitStack(OPND);c=getchar();
    while(c!='#'||GetTop(OPTR)!='#'){
        if(!In(c)){
            Push((OPND),c);c=getchar();
        }
        else{
            switch(Precede(GetTop(OPTR),c)){
            case'<'://栈顶元素优先级低
                Push(OPTR,c);c=getchar();break;
            case'='://脱括号并接收下一字符
                Pop(OPTR,x);c=getchar();break;
            case'>'://退栈并将运算结果入栈
                Pop(OPTR,theta);
                Pop(OPND,b);Pop(OPND,a);
                Push(OPND,Operate(a,theta,b));break;
            }//switch
        }//else
    }//while
    return GetTop(OPND);
}//EvaluateExpression

int main(){
    printf("Input the EvaluateExpression");
    printf("The result is: %d",EvaluateExpression());
    free(OPTR);free(OPND);
    return 0;
}
----------------解决方案--------------------------------------------------------
[bo]急！！！[/bo]
大哥大姐们帮帮忙，为什么会出现 [bo]Segmentation fault at Push[/bo]
谢谢！
----------------解决方案--------------------------------------------------------

修改了 InitStack(SqStack *S)函数；出现Segmentation fault错误，是由于Push(OPTR,'#');  OPTR是野指针；

[[it] 本帖最后由 now 于 2008-4-4 13:32 编辑 [/it]]
----------------解决方案--------------------------------------------------------
哦，谢谢！
----------------解决方案--------------------------------------------------------