问题描述

c++编译通过，运行时弹出窗口说“该内存不能为written”代码如下

//对一串字符串进行分类。
#include
#include
using namespace std;
#define N 256

void getsym(char STR[N],string SYM,string *ID,int *NUM){
char *s;
for(int i=0;i<N;i++) //去空格
{
if(STR[i]!=' ')
{
*s=STR[i];
s++;
}
}
for(i=0;*s!=NULL;i++) //保留字，符号，数字，标识符的识别
{
//识别保留字：var、、const、、begin、end、、while、、do、、read、、write、if、、then、、procedure、、call、、
if((*s=='v')&&((s+1)=='a')&&(*(s+2)=='r'))
{
SYM++="var";
cout<<"VARSYM:var"<<endl;
s=s-3;
}
else if((*s=='c')&&((s+1)=='o')&&(*(s+2)=='n')&&(*(s+3)=='s')&&(*(s+4)='t'))
{
*SYM++="const";
cout<<"CONSTSYM:const"<<endl;
s=s-5;
}

    else if((*s=='b')&&(*(s+1)=='e')&&(*(s+2)=='g')&&(*(s+3)=='i')&&(*(s+4)='n'))
    {
        *SYM++="begin";
        cout<<"BEGINSYM:begin"<<endl;
        s=s-5;
    }

    else if((*s=='e')&&(*(s+1)=='n')&&(*(s+2)=='d'))
    {
        *SYM++="end";
        cout<<"ENDSYM:end"<<endl;
        s=s-3;
    }

    else if((*s=='w')&&(*(s+1)=='h')&&(*(s+2)=='i')&&(*(s+3)=='l')&&(*(s+4)='e'))
    {
        *SYM++="while";
        cout<<"WHILESYM:while"<<endl;
        s=s-5;

    }
    else if((*s=='d')&&(*(s+1)=='o'))
    {
        *SYM++="do";
        cout<<"DOSYM:do"<<endl;
        s=s-2;
    }

    else if((*s=='r')&&(*(s+1)=='e')&&(*(s+2)=='a')&&(*(s+3)=='d'))
    {
        *SYM++="read";
        cout<<"READSYM:read"<<endl;
        s=s-5;
    }

    else if((*s=='w')&&(*(s+1)=='r')&&(*(s+2)=='i')&&(*(s+3)=='t')&&(*(s+4)='e'))
    {
        *SYM++="write";
        cout<<"WRITESYM:write"<<endl;
        s=s-5;
    }

    else if((*s=='i')&&(*(s+1)=='f'))
    {
        *SYM++="if";
        cout<<"IFSYM:if"<<endl;
        s=s-2;
    }
    else if((*s=='t')&&(*(s+1)=='h')&&(*(s+2)=='e')&&(*(s+3)=='n'))
    {
        *SYM++="then";
        cout<<"THENSYM:then"<<endl;
        s=s-4;
    }
    else if((*s=='p')&&(*(s+1)=='r')&&(*(s+2)=='o')&&(*(s+3)=='c')&&(*(s+4)='e')&&(*(s+5)='d')&&(*(s+6)='u')&&(*(s+7)='r')&&(*(s+8)='e'))
    {
        *SYM++="procedure";
        cout<<"PROCEDURESYM:procedure"<<endl;
        s=s-9;
    }
    else if((*s=='c')&&(*(s+1)=='a')&&(*(s+2)=='l')&&(*(s+3)='l'))
    {
        *SYM++="call";
        cout<<"CALLSYM:call"<<endl;
        s=s-4;
    }
    //识别符号
    else if((*s==',')||(*s==';')||(*s==':')||(*s=='=')||(*s=='>')||(*s=='<')||(*s=='!')||(*s=='(')||(*s==')')||(*s=='.'))
    {
        cout<<"symbol："<<*s<<endl;
        s=s-1;
    }
    //识别数字
    else if((*s<58)&&(*s>48))
    {
        *NUM++=*s;
        cout<<"number:"<<*s<<endl;
        s=s-1;
    }
    //识别标识符
    else
    {
        cout<<*s;
        s=s-1;
    }
}

}

int main()
{
char str[N];
string *sym=0,*id=0;
int *num=0;
cout<<"please input the code:n";
for(int i=0;i
{
cin>>str[i];
if(str[i]=='.')
break;
}
getsym(str,sym,id,num);
return 0;
}

解决方案

请先在Debug模式下打开call stack，看看函数调用堆栈，先找到出错的函数调用。