Add Josephus Problem in C++ (Fixes #3332)

archive/c/c-plus-plus/josephus-problem.cpp

@@ -0,0 +1,38 @@
+#include <iostream>
+#include <string>
+#include <stdexcept>
+using namespace std;
+
+int josephus(int n, int k) {
+    if (n == 1)
+        return 1;
+    else
+        return (josephus(n - 1, k) + k - 1) % n + 1;
+}
+
+int main(int argc, char* argv[]) {
+    const string usage_msg = "Usage: please input the total number of people and number of people to skip.\n";
+
+    if (argc != 3) {
+        cerr << usage_msg;
+        return 1;
+    }
+
+    try {
+        int n = stoi(argv[1]);
+        int k = stoi(argv[2]);
+
+        if (n <= 0 || k <= 0) {
+            cerr << usage_msg;
+            return 1;
+        }
+
+        int result = josephus(n, k);
+        cout << result << endl;
+        return 0;
+
+    } catch (...) {
+        cerr << usage_msg;
+        return 1;
+    }
+}