diff --git a/cpp/nth-prime/nth_prime.cpp b/cpp/nth-prime/nth_prime.cpp
index 348460d..92d6dd5 100644
--- a/cpp/nth-prime/nth_prime.cpp
+++ b/cpp/nth-prime/nth_prime.cpp
@@ -1,6 +1,5 @@
 #include "nth_prime.h"
 
-#include <cstddef>
 #include <cstring>
 #include <iostream>
 #include <stdexcept>
@@ -14,7 +13,7 @@ using namespace std;
 number_t nth(size_t n)
 {
     if (n < 1)
-        throw std::domain_error("invalid prime index");
+        throw domain_error("invalid prime index");
 
     vector<number_t> primes = {2, 3, 5, 7, 11, 13};
     primes.reserve(n - 1);
@@ -26,11 +25,12 @@ number_t nth(size_t n)
 
     size_t page = 0;
 
-    while (primes.size() < n) {
+    while (primes.size() < n - 1) {
 
         for (auto p : primes) {
 
-            size_t start = page*sieve_size % p;
+            size_t start = ((page*sieve_size + p - 1)/p)*p
+                - page*sieve_size;
 
             for (size_t i = start; i < sieve_size; i += p) {
 
@@ -38,21 +38,24 @@ number_t nth(size_t n)
             }
         }
 
-        for (auto i : sieve) {
+        for (size_t i = 0; i < sieve_size; ++i) {
 
-            if (!sieve[i]) {
+            if (sieve[i])
+                continue;
 
-                number_t new_prime = page*sieve_size + i;
-                //cout <<  page << " " << i << " " << new_prime << endl;
-                primes.push_back(new_prime);
-                break;
+            number_t p = page*sieve_size + i;
+            primes.push_back(p);
+
+            for (size_t j = i; j < sieve_size; j += p) {
+
+                sieve[j] = true;
             }
         }
 
-        //if (
-        //memset(sieve, 0, sieve_size);
+        memset(sieve, 0, sieve_size);
+        ++page;
     }
-    
+
     return primes[n - 1];
 }