PointPattern, C++ (gcc)

PointPattern

//g++  7.4.0
//PointPattern: printing different patterns using pointer array
//credits for triangle, half triangle, inverted triangle and inverted half triangle codes go to pencilprogrammer.com
//codes for pointer arithmetics and test driver are created by Rezaul Hoque on September 30,2021;contact: jewelmrh@yahoo.com
//note: codes shared by Rezaul Hoque on rextester are not for sale; they are created and shared to facilitate the algorithm learning process; many like Hoque use this platform to practice programming ;Rezaul hopes his contribution helps others to fine tune their learning;

#include <iostream>
using namespace std;
class Pattern {
public:
virtual void print() const {cout<<"No pattern is created.\n";}

};
class Triangle : public Pattern{
public:
void print () const {
  for (int i = 1; i <= 5; i++) {
    for (int p = 1; p<=5-i; p++) {
      cout << " ";
    }
    for (int j = 1; j <2*i; j++) {
      cout << " #";
    }
    cout << "\n";
  }
}

};

class DownTri : public Pattern{
public:
void print () const {
  for (int i = 1; i <= 5; i++) {
    for (int p = 1; p<=i; p++) {
      cout <<" ";
    }
    for (int j = 1; j <= 2*(5-i)+1; j++) {
      cout <<" #";
    }
    cout <<" \n";
  }
}

};

class HalfTri: public Pattern {
public:
void print() const {
for(int l=1; l<=5;l++){
for(int m=1;m<=5;m++){
if(l>=m) 
           std::cout<<" #";}
std::cout<<"\n";}
}

};
class DownHalfTri: public Pattern{
public:
void print() const {
for(int l=1; l<=5;l++){
for(int m=1;m<=5;m++){
if(l<=m) std::cout<<" #";
 }
std::cout<<" \n";}
}
};
int main (){
const int max =4;
Pattern * a[max];//pointer array 
Pattern * point;//pointer to an instance of class Pattern type
int choice;

for (int i=0; i<4; i++)
{
cout <<" (1) Triangle (2) Inverted Triangle (3) Half Triangle (4)Inverted Half Triangle\n";
cin>>choice;
switch(choice)//based on choice of user the pointer indicates the correct derived class
{
case 1: point =  new Triangle;
break;
case 2: point =  new DownTri;
break;
case 3: point =  new HalfTri;
break;
case 4: point = new DownHalfTri;
break;
default: point = new Pattern; break;
}
a[i]=point;//pointer array stores the pointers

}
for (int i=0;i<4;i++)
a[i]->print();
return 0;
}


run \| edit \| history \| help	0