ช่วยดูโค้ดแล้วอธิบายว่าแต่ส่วนทำงานยังไง พอดีผมต้องพรีเซนต์อาจารย์ครับ(กรุณา)

//เป็นโค้ดโรงหนัง ในการจองหนังที่จะดู
#include<iostream>
#include<string>
#include<fstream>
using namespace std;
void menu()
{
//Menu Movie Big C
cout<<"***BIG C MOVIE MENU***\n";
cout<<" 1.Run Program\n";
cout<<" 2.Change Data Movies\n"; //Show enter 3 input store
cout<<" 3.Exit\n";
cout<<" Please select: ";
}
void datas(const char *cinima);
void datam(const char *cinima);
void datal(const char *cinima);
int main()
{
const char *chairs = "c:/chairs.txt"; //Declare constant chairs store c:\xxx
const char *chairm = "c:/chairm.txt"; //Declare constant chairm store c:\xxx
const char *chairl = "c:/chairl.txt"; //Declare constant chairm store c:\xxx
const char *fp="c:/movie.txt";
const char *p;
char ch,Clear;
string word,buffer[30],moviename,therter[3000],therter1[20][20],name;
int choice,select,row,com,r,c;
do
{
system("cls");
menu();
cin>>choice;
if(choice==1)
{
system("cls");
ifstream fin(fp,ios::in);
if(!fin.is_open())
{
cout<<"\nFile not found add movie in menu choice 2\n";
cout<<"Please enter .......\n";
cin>>ch;
}
if(fin.is_open())
{
int i=0;
while(!fin.eof())
{
fin>>word;
buffer[i]=word+"\n";
i++;
}
cout<<"1.Zone1 cinima: "<<buffer[0];
cout<<"2.Zone2 cinima: "<<buffer[1];
cout<<"3.Zone3 cinima: "<<buffer[2]<<endl;
fin.close();
cout<<"Enter choice Cinema : ";
cin>>select;
if(select==1)
{
p=chairs;
name="Zone1 cinima: "+buffer[0];
r=5;
c=9;
}
if(select==2)
{
p=chairm;
name="Zone2 cinima: "+buffer[1];
r=8;
c=11;
}
if(select==3)
{
p=chairl;
name="Zone3 cinima: "+buffer[2];
r=12;
c=13;
}
ifstream fin(p,ios_base::in);
int k=0;
while(!fin.eof())
{
fin>>word;
therter[k]=word;
k++;
}
int n=0;
cout<<r<<" "<<c<<endl;
for(int i=0;i<r;i++)
{
for(int j=0;j<c;j++)
{
therter1[i][j]=therter[n];
n++;
}
}
do
{
system("cls");
cout<<"\t\t\t"<<name<<endl;
cout<<" ";
for(int i=1;i<c;i++)
cout<<" "<<i;
cout<<"\n\n";
for(int i=0;i<r;i+)+
{
for(int j=0;j<c;j++)
cout<<therter1[i][j]<<" ";
cout<<"\n\n";
}
cout<<" 1.Choose\n";
cout<<" 2.Remove\n";
cout<<" 3.Clear\n";
cout<<" 4.Exit menu\n";
cout<<"Select choice: ";
cin>>ch;
if(ch=='1')
{
cout<<"\tEnter Row: ";
cin>>ch;
cout<<"\tEnter Com: ";
cin>>com;
if(ch=='a')row=0;
if(ch=='b')row=1;
if(ch=='c')row=2;
if(ch=='d')row=3;
if(ch=='e')row=4;
if(ch=='f')row=5;
if(ch=='g')row=6;
if(ch=='h')row=7;
if(ch=='i')row=8;
if(ch=='j')row=9;
if(ch=='k')row=10;
if(ch=='l')row=11;
therter1[row][com]="X";
ofstream fout(p,ios::out);
for(int i=0;i<r;i++)
{
for(int j=0;j<c;j++)
fout<<therter1[i][j]<<" ";
fout<<"\n";
}
fout.close();
}
if(ch=='2')
{
cout<<"\tRemove\n";
cout<<"\tEnter Row: ";
cin>>ch;
cout<<"\tEnter Com: ";
cin>>com;
if(ch=='a')row=0;
if(ch=='b')row=1;
if(ch=='c')row=2;
if(ch=='d')row=3;
if(ch=='e')row=4;
if(ch=='f')row=5;
if(ch=='g')row=6;
if(ch=='h')row=7;
if(ch=='i')row=8;
if(ch=='j')row=9;
if(ch=='k')row=10;
if(ch=='l')row=11;
therter1[row][com]="-";
ofstream fout(p,ios::out);
for(int i=0;i<r;i++)
{
for(int j=0;j<c;j++)
fout<<therter1[i][j]<<" ";
fout<<"\n";
}
fout.close();
}
if(ch=='3')
{
cout<<"Clear y/n: ";
cin>>Clear;
if(select==1)
{
switch(Clear)
{
case 'y':datas(chairs);return main();
};
}
if(select==2)
{
switch(Clear)
{
case 'y':datam(chairm);return main();
};
}
if(select==3)
{
switch(Clear)
{
case 'y':datal(chairl);return main();
};
}
}
}
while(ch!='4');
}
}
if(choice==2)
{
system("cls");
ifstream open(fp,ios::in);
if(!open.is_open())
{
if(!open.is_open()) datas(chairs);
if(!open.is_open()) datam(chairm);
if(!open.is_open()) datal(chairl);
ofstream write(fp,ios::out);
for(int i=1;i<=3;i++)
{
cout<<"Enter movie"<<i<<" name: ";
cin>>moviename;
write<<moviename+"\n";
}
}
if(open.is_open())
{
ifstream fin(fp,ios::in);
int i=0;
while(!fin.eof())
{
fin>>word;
buffer[i]=word+"\n";
i++;
}
for(int i=0;i<3;i++)
cout<<i+1<<"."<<buffer[i];
fin.close();
cout<<"Chang movie select: ";
cin>>select;
cout<<"New movie"<<select<<" name: ";
cin>>moviename;
if(select==1)buffer[0]=moviename+"\n";
if(select==2)buffer[1]=moviename+"\n";
if(select==3)buffer[2]=moviename+"\n";
ofstream fout(fp,ios::out);
for(int i=0;i<3;i++)
{
fout<<buffer[i];
}
fout.close();
}

}
}
while(choice!=3);
return 0;
}
void datas(const char *cinima)
{
ofstream fout(cinima,ios::out);
fout<<"A - - - - - - - -\n";
fout<<"B - - - - - - - -\n";
fout<<"C - - - - - - - -\n";
fout<<"D - - - - - - - -\n";
fout<<"E - - - - - - - -\n";
fout.close();
}
void datam(const char *cinima)
{
ofstream fout(cinima,ios::out);
fout<<"A - - - - - - - - - -\n";
fout<<"B - - - - - - - - - -\n";
fout<<"C - - - - - - - - - -\n";
fout<<"D - - - - - - - - - -\n";
fout<<"E - - - - - - - - - -\n";
fout<<"F - - - - - - - - - -\n";
fout<<"G - - - - - - - - - -\n";
fout<<"H - - - - - - - - - -\n";
fout.close();
}
void datal(const char *cinima)
{
ofstream fout(cinima,ios::out);
fout<<"A - - - - - - - - - - - -\n";
fout<<"B - - - - - - - - - - - -\n";
fout<<"C - - - - - - - - - - - -\n";
fout<<"D - - - - - - - - - - - -\n";
fout<<"E - - - - - - - - - - - -\n";
fout<<"F - - - - - - - - - - - -\n";
fout<<"G - - - - - - - - - - - -\n";
fout<<"H - - - - - - - - - - - -\n";
fout<<"I - - - - - - - - - - - -\n";
fout<<"J - - - - - - - - - - - -\n";
fout<<"K - - - - - - - - - - - -\n";
fout<<"L - - - - - - - - - - - -\n";
fout.close();
}