Given with the n P r, where P represents Permutation, n represents total numbers and r represents arrangement the task is to calculate the value of nPr.
Permutation is the arrangement of data in a sequence or order. Permutation and combination differs in the sense that permutation is the process of arranging whereas combination is the process of selection of elements from the given set.
Formula for permutation is −
nPr = (n!)/(n-r)!
Example
Input-: n=5 r=2 Output-: 20
Algorithm
Start Step 1 -> declare function to calculate value of nPr int cal_n(int n) IF n <=1 Return 1 End return n*cal_n(n-1) Step 2 -> Declare function to calculate the final npr int nPr(int n, int r) return cal_n(n)/cal_n(n-r) Step 3 -> In main() Declare variables as int n=5, r=2 Print nPr(n, r) Stop
Example
#include<stdio.h>
//function to calculate the factorial for npr
int cal_n(int n){
if (n <= 1)
return 1;
return n*cal_n(n-1);
}
//function to calculate the final npr
int nPr(int n, int r){
return cal_n(n)/cal_n(n-r);
}
int main(){
int n=5, r=2;
printf("value of %dP%d is %d", n, r, nPr(n, r));
return 0;
}Output
value of 5P2 is 20