Question

How to calculate value of nPr in Rust

Answer 1

// Permutations Calculator - finds the number of subsets that can be taken from a set
 
fn factorial(n:i32)->i32 {
    return if n == 1 || n == 0 { 1 } else { return n * factorial(n - 1) };
}
 
fn main() {
    let n:i32 = 7;
    let r:i32 = 3;
 
    let npr:i32 = factorial(n) / factorial(n - r);
 
    println!("nPr = {}", npr);
}
 
 
 
 
/*
run:
   
nPr = 210
   
*/

 

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