指针和数组存储区

    char *quot = "l1302-C-11250";   // *quot是字符串常量，存放在静态存储区
    char *p = quot;
    while(*p != '\0'){
        if(*p == '-'){
            *p = '_';   //出错
        }
        p++;
    }

   char quot[20] = "l1302-C-11250";　//字符数组，存放在堆栈中
    char *p = quot;
    while(*p != '\0'){
        if(*p == '-'){
            *p = '_';　//正确
        }
        p++;
    }