Use range-based for loops (C++11) when looping over vector elements

src/validation.cpp

@@ -309,7 +309,6 @@ bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool
     return EvaluateSequenceLocks(index, lockPair);
 }
 
-
 void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
     int expired = pool.Expire(GetTime() - age);
     if (expired != 0) {
@@ -2817,8 +2816,8 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Co
 
     // No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam
     if (!fHaveWitness) {
-        for (size_t i = 0; i < block.vtx.size(); i++) {
-            if (block.vtx[i]->HasWitness()) {
+      for (const auto& tx : block.vtx) {
+            if (tx->HasWitness()) {
                 return state.DoS(100, false, REJECT_INVALID, "unexpected-witness", true, strprintf("%s : unexpected witness data found", __func__));
             }
         }