Create find_maximum_of_n_numbers.dart (#5714)

A program to calculate maximum number in n numbers.

program/program/find-maximum-of-n-numbers/find_maximum_of_n_numbers.dart

@@ -0,0 +1,22 @@
+import 'dart:io';
+
+void main() {
+  stdout.write('Enter the number of numbers you want to check: ');
+  int? n = int.parse(stdin.readLineSync()!);
+  List<int> a = [];
+
+  for (int i = 0; i < n; i++) {
+    stdout.write('Enter the number [${i + 1}]: ');
+    int number = int.parse(stdin.readLineSync()!);
+    a.add(number);
+  }
+
+  int max = a[0];
+  for (int i = 0; i < n; i++) {
+    if (a[i] > max) {
+      max = a[i];
+    }
+  }
+
+  print('The Max number is: $max');
+}