//CODE TO GENERATE ALL THE SUBSEQUENCES OF A 
#include <iostream>
using namespace std;
void subsequences(char in[],char out[],int i,int j)
{
	if(in[i]=='\0')
	{
		out[j]='\0';
		cout<<out<<"\n";
		return;
	}
	//RECURSIVE CASE EITHER INCLUDE.
	out[j]=in[i];
	subsequences(in,out,i+1,j+1);
	//EXCLUDING PART RECURSIVE CASE.
	out[j]='\0';
	subsequences(in,out,i+1,j);
}
int main() {
	// your code goes here
	char a[]="abcd",b[1000];
	subsequences(a,b,0,0);
	return 0;
}

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