# C++ > Mathematics Code Examples

## Program to print all possible permutations of first n natural nos

``` Program to print all possible permutations 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<<" "; } //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 : "; 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 ```