diff --git a/src/primitives/block.cpp b/src/primitives/block.cpp
--- a/src/primitives/block.cpp
+++ b/src/primitives/block.cpp
@@ -21,8 +21,8 @@
                    "vtx=%u)\n",
                    GetHash().ToString(), nVersion, hashPrevBlock.ToString(),
                    hashMerkleRoot.ToString(), nTime, nBits, nNonce, vtx.size());
-    for (unsigned int i = 0; i < vtx.size(); i++) {
-        s << "  " << vtx[i]->ToString() << "\n";
+    for (const auto &tx : vtx) {
+        s << "  " << tx->ToString() << "\n";
     }
     return s.str();
 }
diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
--- a/src/primitives/transaction.cpp
+++ b/src/primitives/transaction.cpp
@@ -73,10 +73,9 @@
 
 Amount CTransaction::GetValueOut() const {
     Amount nValueOut = Amount::zero();
-    for (std::vector<CTxOut>::const_iterator it(vout.begin()); it != vout.end();
-         ++it) {
-        nValueOut += it->nValue;
-        if (!MoneyRange(it->nValue) || !MoneyRange(nValueOut)) {
+    for (const auto &tx_out : vout) {
+        nValueOut += tx_out.nValue;
+        if (!MoneyRange(tx_out.nValue) || !MoneyRange(nValueOut)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }