910. The arithmetic mean of positive

The sequence of real numbers is given. Find the arithmetic mean of positive numbers.

Input. The first line contains amount n (0 < n ≤ 100) of real numbers. Next line contains n real numbers, each of them is not greater than 100 by absolute value.

Output. Print the arithmetic mean of positive numbers with 2 digits after decimal point. If the positive numbers do not appear in the sequence, print “Not Found” (without quotes).

Sample input 1	Sample output 1
3 5.2 -2 4	4.60
Sample input 2	Sample output 2
3 -5.2 -2 -4	Not Found

SOLUTION

loops

Algorithm analysis

Сount the sum of positive numbers in the variable s, and their amount in the variable cnt. The answer is s / cnt.

Algorithm realization

Read the value of n.

s = cnt = 0;

scanf("%d",&n);

Read n input numbers.

for(i = 0; i < n; i++)

{

scanf("%lf",&val);

If the number val is positive, then add it to the sum s and increase the number of positive numbers cnt by 1.

if (val > 0)

{

s += val;

cnt++;

}

}

Depending on the amount of positive numbers cnt, print the answer.

if (cnt == 0) printf("Not Found\n");

else printf("%.2lf\n",s / cnt);

Java realization

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

int n = con.nextInt();

double s = 0;

int cnt = 0;

for(int i = 0; i < n; i++)

{

double val = con.nextDouble();

if (val > 0)

{

s += val;

cnt++;

}

}

if (cnt == 0) System.out.println("Not Found");

else

System.out.printf("%.2f\n", s / cnt);

con.close();

}

}

Python realization

n = int(input())

lst = list(map(float, input().split()))

l = []

for i in range(n):

if lst[i] > 0: l.append(lst[i])

if len(l) > 0:

average = float(sum(l) / len(l))

print('%.2f' % average)

else:

print('Not Found')