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Displaying Source Code(s)
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PROGRAM TO PRINT ALL POSSIBLE PERMUTATIONS OF FIRST N NAUTURAL
NOs
--------------------------------------------------------------------------------
Description : Not Specified
//PROGRAM TO PRINT ALL POSSIBLE PERMUTATIONS
//OF FIRST N NAUTURAL NOS
/******************************************/
/* DEVELOPED BY :- */
/* SHIKHA JAIN */
/******************************************/
/*
/* MAIN LOGIC :
/*PERMUTATIONS CAN BE FIND OUT BY LEFT SHIFTING AS FOLLOWS
/*
/* 1234
/* / | |
/* 2341 3412 4123 1234 //AFTER SHIFTING ALL THE N
DIGITS
/* / | / | / | / |
/*2413 2134 2341 . . . 4231 4312 4123 . . . //KEEPING FIRST
DIGIT
FIXED
/* / / / / / / / / / / / /
/* 2143 2134 4213 4231 .............. //KEEPING 1 & 2 DIGITS
FIXED
/*
/*LIKEWISE AFTER THE LAST STEP THAT IS KEEPING ALL THE DIGITS
FIXED
/*EXCEPT TH ELAST ONE & DO SHIFTING WITH THOSE TWO DIGITS, WE
WILL
/*GET n! LEAF NODE SUCH THAT EACH NODE IS REPRESENTING A NEW
/*ARRANGEMENT OF FIRST N NATURAL NOS.
/******************************************/
//header files
#include<iostream.h>
#include<conio.h>
#include<string.h>
int count=0;
//func to display the sequence
void dis(char a[],int n)
{
for(int jk=n-1;jk>=0;jk--)
{
cout<<a[jk];
}
cout<<"<BR>;
}
//function to left shift last n elements
//of the array by one position
void shift(char a[],int n)
{
char s;
s=a[n-1];
for(int i=n-1;i>0;i--)
a[i]=a[i-1];
a[0]=s;
}
//func to find all possible arrangements
void per(char a[],int m,int n)
{
for(int i=0;i<m;i++)
{
if(m>1)
{
shift(a,m);
per(a,m-1,n); //genetrating the tree
}
else
{
dis(a,n); //displaying the leaf nodes of the tree
count++;
}
}
}
void main()
{
// char *a;
int n;
clrscr();
cout<<"Enter a no : ";
cin>>n;
char *a = new (char[n]);
for(int i=0;i<n;i++)
a[i] = n-i+48;
// dis(a,n);
cout<<"Possible permutations are :<BR>;
per(a,n,n);
cout<<"Total No Of Permutations Is "<<count;
getch();
}
/**************************************/
OUTPUT
------
Enter a no : 3
Possible permutations are :
213
231
321
312
132
123
Total No Of Permutations Is 6
/**************************************/
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123
Eng