Short C++ solution thanks to Bignum library support.

10/euler10.cpp

@@ -0,0 +1,48 @@
+// This solution needs the GNU MP Bignum library
+// g++ euler10.cpp -o euler10 -lgmpxx -lgmp
+
+#include <gmpxx.h>
+#include <cmath>
+#include <vector>
+#include <iostream>
+
+void sieve(std::vector<int>& primes, int const limit) {
+    if (limit < 2) {
+        return;
+    } else if (limit < 3) {
+        primes.push_back(2);
+        return;
+    }
+    primes.push_back(2);
+    primes.push_back(3);
+
+    for (int num = 5; num <= limit; num += 2) {
+        int sqrtnum = (int) std::sqrt(num);
+        bool isPrime = true;
+        for (auto primeIt = ++primes.begin(); primeIt != primes.end() && *primeIt <= sqrtnum; ++primeIt) {
+            if (num % *primeIt == 0) {
+                isPrime = false;
+                break;
+            }
+        }
+        if (isPrime) {
+            primes.push_back(num);
+        }
+    }
+}
+
+int main(void) {
+    constexpr int limit = 2000000;
+    constexpr int PRIMELIMIT = limit - 1;
+    std::vector<int> primes;
+    sieve(primes, PRIMELIMIT);
+
+    mpz_class sum = 0;
+
+    for (auto primeIt = primes.begin(); primeIt != primes.end(); ++primeIt) {
+        sum += *primeIt;
+    }
+
+    std::cout << sum << std::endl;
+    return EXIT_SUCCESS;
+}