Merge pull request matthewsamuel95#822 from paolaguarasci/binomialCPP

binomial coeff in cpp

Author: matthewsamuel95

Math/binomial_coefficients/binomial.cpp

@@ -0,0 +1,69 @@
+/*
+   Binomial Coeff
+ */
+
+#include <iostream>
+#include <climits>
+#include <stdlib.h>
+using namespace std;
+
+int fact(int);
+int coeff(int, int);
+bool check(char **, char **);
+bool isNum(char *c);
+
+int main(int argc, char *argv[])
+{
+
+  if (argc != 3 || check(&argv[1], &argv[2]))
+  {
+    cout << "How to use\n\t$ ./bc n k\nwith n,k positive integer and n >= k." << endl;
+    return -1;
+  }
+
+  int n = atoi(argv[1]);
+  int k = atoi(argv[2]);
+
+  cout << "With n = " << n
+       << " and k = " << k
+       << " the binomial coeffivients is "
+       << coeff(n, k)
+       << endl;
+
+  return 0;
+}
+
+int fact(int n)
+{
+  if (n == 1 || n == 0)
+  {
+    return 1;
+  }
+  return n * fact(n - 1);
+}
+
+int coeff(int n, int k)
+{
+  return fact(n) / (fact(k) * fact(n - k));
+}
+
+bool check(char **n, char **k)
+{
+  if ((!isNum(*n) || !isNum(*k)) || atoi(*n) < atoi(*k) || (atoi(*n) < 0 || atoi(*k) < 0))
+  {
+    return true;
+  }
+  return false;
+}
+
+bool isNum(char *c)
+{
+  for (int i = 0; c[i]; i++)
+  {
+    if (!isdigit(c[i]))
+    {
+      return false;
+    }
+  }
+  return true;
+}