MFC.cpp
// Problem definition by Eli Tilevich:
// Well, I guess I would like to code a simple registration system with a very
// limited functionality which
// would only allow students register for classes, cancel classes, and delete
// students from the system.
// Basically, it would be something very similar to test18e.c; however I would
// like to specifically concentrate on
// handling the many-to-many relation between students and classes. I would
// like to answer the question of which
// facilities in different class libraries help the programmer handle this
// non-trivial software paradigm.
// --------------------------------------------------------------------------
// Program coded by Eli Tilevich, Nov.28/99
#include <stdio.h>
#include <string.h>
#include <afxtempl.h>
long starttime;
#define TASK(s) printf("%s", s);
#define CIN starttime = clock();
#define COUT printf("%d\t", clock()-starttime);
#define NL printf("\n")
#define EQ_STR(s1, s2) (strcmp(s1, s2) == 0)
class Student;
class Class;
class Takes;
typedef CTypedPtrList<CPtrList, Student*> Student_list;
typedef CTypedPtrList<CPtrList, Class*> Class_list;
typedef CTypedPtrList<CPtrList, Takes*> Takes_list;
// School encapsulates your problem
class School {
Student_list lstStudents;
Class_list lstClasses;
Takes_list lstSC;
public:
static char *getName(int i,char *buf);
Class* add_class(const char * name);
Student * add_student(const char * name);
Student * find_student(const char * name);
void list_student_classes(Student * sp);
Takes* find_student_class(const Student *sp, const char * class_name);
Class* find_class(const char * name);
void add_student_class(Student * sp, Class * cp);
void delete_student_class(Takes * tp);
void delete_student(Student * sp);
};
class Student {
char strName[1<<5];
public:
Student(const char *name){
strcpy(strName, name);
}
const char * GetName() const { return strName; }
};
class Class {
char strName[1<<5];
public:
Class(const char *name){
strcpy(strName, name);
}
const char * GetName() const { return strName; }
};
class Takes {
int mark;
int absentDays;
Student *sp;
Class *cp;
public:
Takes(Student *s = 0, Class *c = 0) : sp(s), cp(c) {}
Student * GetStudent() const { return sp; }
Class * GetClass() const { return cp; }
int addAbsent(int d){absentDays+=d; return absentDays;} // for d=0 reports
int getMark(){return mark;}
void setMark(int m){mark=m;}
};
// pick up names including spaces, if i>0 skip the first word
char* School::getName(int i,char *buf){
char *p;
for(p=buf; *p!='\n'; p++)continue;
*p='\0'; // mark the end of the name
if(i==0)return buf;
for(p=buf; *p!='\0' && *p!=' '; p++)continue;
if(*p=='\0')return p;
for( ;*p==' ' && *p!='\0'; p++);
return p;
}
Student * School::add_student(const char * name){
printf("new student=%s\n",name);
Student * sp=new Student(name);
lstStudents.AddTail(sp);
return sp;
}
Class * School::add_class(const char * name){
//printf("... new class\n");
Class * cp = new Class(name);
lstClasses.AddTail(cp);
return cp;
}
Student * School::find_student(const char * name){
Student * sp = NULL;
POSITION pos = lstStudents.GetHeadPosition();
while(pos != NULL){
sp = lstStudents.GetNext(pos);
if(EQ_STR(sp->GetName(), name))
return sp;
}
return NULL;
}
void School::list_student_classes(Student * sp){
printf("%s is enrolled in:\n", sp->GetName());
Takes * tp;
POSITION pos = lstSC.GetHeadPosition();
while(pos != NULL){
tp = lstSC.GetNext(pos);
if(EQ_STR(tp->GetStudent()->GetName(), sp->GetName()))
printf("%s\n", tp->GetClass()->GetName());
}
}
Takes* School::find_student_class(const Student *sp, const char * class_name){
Takes * tp;
POSITION pos = lstSC.GetHeadPosition();
while(pos != NULL){
tp = lstSC.GetNext(pos);
if(EQ_STR(tp->GetStudent()->GetName(), sp->GetName()) &&
EQ_STR(tp->GetClass()->GetName(), class_name))
return tp;
}
return NULL;
}
Class * School::find_class(const char * name){
Class *cp;
POSITION pos = lstClasses.GetHeadPosition();
while(pos != NULL){
cp = lstClasses.GetNext(pos);
if(EQ_STR(cp->GetName(), name))
return cp;
}
return NULL;
}
void School::add_student_class(Student * sp, Class * cp){
Takes * tp = new Takes(sp, cp);
lstSC.AddTail(tp);
}
void School::delete_student_class(Takes * tp){
Takes * t;
POSITION pos = lstSC.GetHeadPosition();
while(pos != NULL){
t = lstSC.GetNext(pos);
if(t == tp){
lstSC.RemoveAt(pos);
delete tp;
break;
}
}
}
void School::delete_student(Student * sp){
TASK("Timing the performace of School::delete_student (MFC)\n");
CIN;
//delete Student's Takes relations
Takes * t;
POSITION pos = lstSC.GetHeadPosition();
while(pos != NULL){
POSITION del = pos;
t = lstSC.GetNext(pos);
if(EQ_STR(t->GetStudent()->GetName(), sp->GetName())){
lstSC.RemoveAt(del);
delete t;
}
}
pos = lstStudents.Find(sp);
//delete Student
lstStudents.RemoveAt(pos);
delete sp;
COUT;
NL;
}
#define BSIZE 80
char buff[BSIZE];
main(int argc,char **argv) {
School *school; Student *sp; Takes *tp; Class *cp;
char *name,cc;
school=new School;
for(;;){
printf("type your name:\n");
fgets(buff,BSIZE,stdin);
name=school->getName(0,buff);
if(!strcmp(name,"STOP"))break;
sp = school->find_student(name);
if(sp){
if(strcmp(name, "eli") != 0)
school->list_student_classes(sp);
}
else {
sp = school->add_student(name);
//Generate test data for timing
if(strcmp(name, "eli") == 0){
char class_name[1<<5];
for(int cl = 0; cl < 100000; cl ++){
sprintf(class_name, "CS%d", cl);
cp = school->add_class(class_name);
school->add_student_class(sp, cp);
}
}
}
for(;;){
printf("menu(A className,D className,R=remove student,E=exit):\n");
fgets(buff,BSIZE,stdin);
sscanf(buff,"%c",&cc);
name = school->getName(1,buff);
if(cc=='A'){
// first check that this student isn't already registered there
tp = school->find_student_class(sp, name);
if(tp){ printf("... you are already registered\n"); continue;}
// find the class
cp = school->find_class(name);
if(!cp){
cp = school->add_class(name);
}
school->add_student_class(sp, cp);
}
else if(cc=='D'){
tp = school->find_student_class(sp, name);
if(!tp){
printf(" you are not registered for this class\n");
continue;
}
school->delete_student_class(tp);
}
else if(cc=='R'){
school->delete_student(sp);
break;
}
else if(cc=='E')break;
else printf("unknown command=%c\n",cc);
}
}
return(0);
}