explain the following program

#include<iostream.h>
#include<conio.h>
#define s 20
class matrix
{
int a[s][s],x,y;
public:
void get();
void put();
matrix operator+(matrix);
matrix operator-(matrix);
matrix operator*(matrix);
matrix transpose();
};
void matrix::get()
{
cout<<"enter the order of matrix \n";
cin>>x>>y;
cout<<"enter the matrix \n";
for(int i=0;i<x;i++)>
for(int j=0;j<y;j++)>
cin>>a[i][j];
}
void matrix::put()
{
cout<<"the ans is: \n";
for(int i=0;i<x;i++)>
{
cout<<"\n \t";
for(int j=0;j<y;j++)>
cout<<a[i][j]<<"   ";
}
}
matrix matrix::operator+(matrix b)
{
matrix r;
if((x!=b.x)||(y!=b.y))
{
cout<<"\n \t matrix addition is not possible the result is incorrect \n\n";
r.x=0;
r.y=0;
}
else
{
r.x=x;
r.y=y;
}
for(int i=0;i<x;i++)>
for(int j=0;j<y;j++)>
r.a[i][j]=a[i][j]+b.a[i][j];
return r;
}
matrix matrix::operator-(matrix b)
{
matrix r;
if((x!=b.x)||(y!=b.y))
{
cout<<"\n \t matrix subtraction is not possible the result is incorrect \n \n";
r.x=0;
r.y=0;
}
else
{
r.x=x;
r.y=y;
}
for(int i=0;i<x;i++)>
for(int j=0;j<y;j++)>
r.a[i][j]=a[i][j]-b.a[i][j];
return r;
}
matrix matrix::operator*(matrix b)
{
matrix r;
if((x!=b.y)||(y!=b.x))
{
cout<<"\n \t matrix multiplication is not possible the result is incorrect \n\n";
r.x=0;
r.y=0;
}
else
{
r.x=x;
r.y=b.y;
}
for(int i=0;i<s;i++)>
for(int j=0;j<s;j++)>
r.a[i][j]=0;
for(i=0;i<x;i++)>
for(j=0;j<b.y;j++)>
for(int k=0;(k<y)||(k><b.x);k++)>
r.a[i][j]+=a[i][k]*b.a[k][j];
return r;
}
matrix matrix::transpose()
{
matrix r;
for(int i=0;i<x;i++)>
for(int j=0;j<y;j++)>
r.a[i][j]=a[j][i];
r.x=x;
r.y=y;
return r;
}
void main()
{
clrscr();
char op;
matrix a,b,c;
int t=1;
while(t)
{
cout<<"\t select option \n \n 1)matrix addition\n 2)matrix subtraction \n 3)matrix multiplication \n 4)matrix transpose \n 5)exit \n";
op=getch();
switch(op)
{
case '1':
cout<<"\n \t matrix addition \n";
a.get();
b.get();
c=a+b;
c.put();
break;
case '2':
cout<<"\n \t matrix subtraction \n";
a.get();
b.get();
c=a-b;
c.put();
break;
case'3':
cout<<"\n \t matrix multiplication \n";
a.get();
b.get();
c=a*b;
c.put();
break;
case'4':
cout<<"\n \t matrix transpose \n";
a.get();
c=a.transpose();
c.put();
break;
case'5':
cout<<"\n \t press any key to exit \n";
t=0;
break;
default:
cout<<"\n \t enter a valid option \n";
}
getch();
}
getch();
}