diff --git a/src/bench/crypto_hash.cpp b/src/bench/crypto_hash.cpp
index 2914a36c7b92a..410a08e512cbf 100644
--- a/src/bench/crypto_hash.cpp
+++ b/src/bench/crypto_hash.cpp
@@ -47,7 +47,7 @@ static void SHA256_32b(benchmark::State& state)
     std::vector<uint8_t> in(32,0);
     while (state.KeepRunning()) {
         for (int i = 0; i < 1000000; i++) {
-            CSHA256().Write(in.data(), in.size()).Finalize(&in[0]);
+            CSHA256().Write(in.data(), in.size()).Finalize(in.data());
         }
     }
 }
diff --git a/src/qt/signverifymessagedialog.cpp b/src/qt/signverifymessagedialog.cpp
index 4e37b816545ea..cba9d4da38113 100644
--- a/src/qt/signverifymessagedialog.cpp
+++ b/src/qt/signverifymessagedialog.cpp
@@ -162,7 +162,7 @@ void SignVerifyMessageDialog::on_signMessageButton_SM_clicked()
     ui->statusLabel_SM->setStyleSheet("QLabel { color: green; }");
     ui->statusLabel_SM->setText(QString("<nobr>") + tr("Message signed.") + QString("</nobr>"));
 
-    ui->signatureOut_SM->setText(QString::fromStdString(EncodeBase64(&vchSig[0], vchSig.size())));
+    ui->signatureOut_SM->setText(QString::fromStdString(EncodeBase64(vchSig.data(), vchSig.size())));
 }
 
 void SignVerifyMessageDialog::on_copySignatureButton_SM_clicked()
diff --git a/src/qt/test/paymentservertests.cpp b/src/qt/test/paymentservertests.cpp
index c7830071ed0a4..273bd1048720a 100644
--- a/src/qt/test/paymentservertests.cpp
+++ b/src/qt/test/paymentservertests.cpp
@@ -24,7 +24,7 @@ X509 *parse_b64der_cert(const char* cert_data)
 {
     std::vector<unsigned char> data = DecodeBase64(cert_data);
     assert(data.size() > 0);
-    const unsigned char* dptr = &data[0];
+    const unsigned char* dptr = data.data();
     X509 *cert = d2i_X509(nullptr, &dptr, data.size());
     assert(cert);
     return cert;
@@ -43,7 +43,7 @@ static SendCoinsRecipient handleRequest(PaymentServer* server, std::vector<unsig
     // Write data to a temp file:
     QTemporaryFile f;
     f.open();
-    f.write((const char*)&data[0], data.size());
+    f.write((const char*)data.data(), data.size());
     f.close();
 
     // Create a QObject, install event filter from PaymentServer
@@ -139,7 +139,7 @@ void PaymentServerTests::paymentServerTests()
 
     // Contains a testnet paytoaddress, so payment request network doesn't match client network:
     data = DecodeBase64(paymentrequest1_cert2_BASE64);
-    byteArray = QByteArray((const char*)&data[0], data.size());
+    byteArray = QByteArray((const char*)data.data(), data.size());
     r.paymentRequest.parse(byteArray);
     // Ensure the request is initialized, because network "main" is default, even for
     // uninitialized payment requests and that will fail our test here.
@@ -148,7 +148,7 @@ void PaymentServerTests::paymentServerTests()
 
     // Expired payment request (expires is set to 1 = 1970-01-01 00:00:01):
     data = DecodeBase64(paymentrequest2_cert2_BASE64);
-    byteArray = QByteArray((const char*)&data[0], data.size());
+    byteArray = QByteArray((const char*)data.data(), data.size());
     r.paymentRequest.parse(byteArray);
     // Ensure the request is initialized
     QVERIFY(r.paymentRequest.IsInitialized());
@@ -159,7 +159,7 @@ void PaymentServerTests::paymentServerTests()
     // 9223372036854775807 (uint64), 9223372036854775807 (int64_t) and -1 (int32_t)
     // -1 is 1969-12-31 23:59:59 (for a 32 bit time values)
     data = DecodeBase64(paymentrequest3_cert2_BASE64);
-    byteArray = QByteArray((const char*)&data[0], data.size());
+    byteArray = QByteArray((const char*)data.data(), data.size());
     r.paymentRequest.parse(byteArray);
     // Ensure the request is initialized
     QVERIFY(r.paymentRequest.IsInitialized());
@@ -170,7 +170,7 @@ void PaymentServerTests::paymentServerTests()
     // 9223372036854775808 (uint64), -9223372036854775808 (int64_t) and 0 (int32_t)
     // 0 is 1970-01-01 00:00:00 (for a 32 bit time values)
     data = DecodeBase64(paymentrequest4_cert2_BASE64);
-    byteArray = QByteArray((const char*)&data[0], data.size());
+    byteArray = QByteArray((const char*)data.data(), data.size());
     r.paymentRequest.parse(byteArray);
     // Ensure the request is initialized
     QVERIFY(r.paymentRequest.IsInitialized());
@@ -190,7 +190,7 @@ void PaymentServerTests::paymentServerTests()
 
     // Payment request with amount overflow (amount is set to 21000001 BTC):
     data = DecodeBase64(paymentrequest5_cert2_BASE64);
-    byteArray = QByteArray((const char*)&data[0], data.size());
+    byteArray = QByteArray((const char*)data.data(), data.size());
     r.paymentRequest.parse(byteArray);
     // Ensure the request is initialized
     QVERIFY(r.paymentRequest.IsInitialized());
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index 2037ebe3c47d8..f8cdf57d14fe7 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -371,7 +371,7 @@ UniValue signmessagewithprivkey(const JSONRPCRequest& request)
     if (!key.SignCompact(ss.GetHash(), vchSig))
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Sign failed");
 
-    return EncodeBase64(&vchSig[0], vchSig.size());
+    return EncodeBase64(vchSig.data(), vchSig.size());
 }
 
 UniValue setmocktime(const JSONRPCRequest& request)
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index f9716dfc664fc..7315500e3b6d3 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -1366,7 +1366,7 @@ static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion,
             stack = std::vector<std::vector<unsigned char> >(witness.stack.begin(), witness.stack.end() - 1);
             uint256 hashScriptPubKey;
             CSHA256().Write(&scriptPubKey[0], scriptPubKey.size()).Finalize(hashScriptPubKey.begin());
-            if (memcmp(hashScriptPubKey.begin(), &program[0], 32)) {
+            if (memcmp(hashScriptPubKey.begin(), program.data(), 32)) {
                 return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH);
             }
         } else if (program.size() == 20) {
diff --git a/src/test/bip32_tests.cpp b/src/test/bip32_tests.cpp
index c851ab2849077..e123c26ad0277 100644
--- a/src/test/bip32_tests.cpp
+++ b/src/test/bip32_tests.cpp
@@ -91,7 +91,7 @@ void RunTest(const TestVector &test) {
     std::vector<unsigned char> seed = ParseHex(test.strHexMaster);
     CExtKey key;
     CExtPubKey pubkey;
-    key.SetMaster(&seed[0], seed.size());
+    key.SetMaster(seed.data(), seed.size());
     pubkey = key.Neuter();
     for (const TestDerivation &derive : test.vDerive) {
         unsigned char data[74];
diff --git a/src/test/bloom_tests.cpp b/src/test/bloom_tests.cpp
index 2085b5cb2b87f..9274ceefcb3dd 100644
--- a/src/test/bloom_tests.cpp
+++ b/src/test/bloom_tests.cpp
@@ -154,8 +154,8 @@ BOOST_AUTO_TEST_CASE(bloom_match)
     COutPoint prevOutPoint(uint256S("0x90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b"), 0);
     {
         std::vector<unsigned char> data(32 + sizeof(unsigned int));
-        memcpy(&data[0], prevOutPoint.hash.begin(), 32);
-        memcpy(&data[32], &prevOutPoint.n, sizeof(unsigned int));
+        memcpy(data.data(), prevOutPoint.hash.begin(), 32);
+        memcpy(data.data()+32, &prevOutPoint.n, sizeof(unsigned int));
         filter.insert(data);
     }
     BOOST_CHECK_MESSAGE(filter.IsRelevantAndUpdate(tx), "Simple Bloom filter didn't match manually serialized COutPoint");
diff --git a/src/test/crypto_tests.cpp b/src/test/crypto_tests.cpp
index 391ad14ffa1e8..c748b2448c3eb 100644
--- a/src/test/crypto_tests.cpp
+++ b/src/test/crypto_tests.cpp
@@ -58,12 +58,12 @@ void TestRIPEMD160(const std::string &in, const std::string &hexout) { TestVecto
 
 void TestHMACSHA256(const std::string &hexkey, const std::string &hexin, const std::string &hexout) {
     std::vector<unsigned char> key = ParseHex(hexkey);
-    TestVector(CHMAC_SHA256(&key[0], key.size()), ParseHex(hexin), ParseHex(hexout));
+    TestVector(CHMAC_SHA256(key.data(), key.size()), ParseHex(hexin), ParseHex(hexout));
 }
 
 void TestHMACSHA512(const std::string &hexkey, const std::string &hexin, const std::string &hexout) {
     std::vector<unsigned char> key = ParseHex(hexkey);
-    TestVector(CHMAC_SHA512(&key[0], key.size()), ParseHex(hexin), ParseHex(hexout));
+    TestVector(CHMAC_SHA512(key.data(), key.size()), ParseHex(hexin), ParseHex(hexout));
 }
 
 void TestAES128(const std::string &hexkey, const std::string &hexin, const std::string &hexout)
@@ -76,13 +76,13 @@ void TestAES128(const std::string &hexkey, const std::string &hexin, const std::
     assert(key.size() == 16);
     assert(in.size() == 16);
     assert(correctout.size() == 16);
-    AES128Encrypt enc(&key[0]);
+    AES128Encrypt enc(key.data());
     buf.resize(correctout.size());
     buf2.resize(correctout.size());
-    enc.Encrypt(&buf[0], &in[0]);
+    enc.Encrypt(buf.data(), in.data());
     BOOST_CHECK_EQUAL(HexStr(buf), HexStr(correctout));
-    AES128Decrypt dec(&key[0]);
-    dec.Decrypt(&buf2[0], &buf[0]);
+    AES128Decrypt dec(key.data());
+    dec.Decrypt(buf2.data(), buf.data());
     BOOST_CHECK_EQUAL(HexStr(buf2), HexStr(in));
 }
 
@@ -96,12 +96,12 @@ void TestAES256(const std::string &hexkey, const std::string &hexin, const std::
     assert(key.size() == 32);
     assert(in.size() == 16);
     assert(correctout.size() == 16);
-    AES256Encrypt enc(&key[0]);
+    AES256Encrypt enc(key.data());
     buf.resize(correctout.size());
-    enc.Encrypt(&buf[0], &in[0]);
+    enc.Encrypt(buf.data(), in.data());
     BOOST_CHECK(buf == correctout);
-    AES256Decrypt dec(&key[0]);
-    dec.Decrypt(&buf[0], &buf[0]);
+    AES256Decrypt dec(key.data());
+    dec.Decrypt(buf.data(), buf.data());
     BOOST_CHECK(buf == in);
 }
 
@@ -114,16 +114,16 @@ void TestAES128CBC(const std::string &hexkey, const std::string &hexiv, bool pad
     std::vector<unsigned char> realout(in.size() + AES_BLOCKSIZE);
 
     // Encrypt the plaintext and verify that it equals the cipher
-    AES128CBCEncrypt enc(&key[0], &iv[0], pad);
-    int size = enc.Encrypt(&in[0], in.size(), &realout[0]);
+    AES128CBCEncrypt enc(key.data(), iv.data(), pad);
+    int size = enc.Encrypt(in.data(), in.size(), realout.data());
     realout.resize(size);
     BOOST_CHECK(realout.size() == correctout.size());
     BOOST_CHECK_MESSAGE(realout == correctout, HexStr(realout) + std::string(" != ") + hexout);
 
     // Decrypt the cipher and verify that it equals the plaintext
     std::vector<unsigned char> decrypted(correctout.size());
-    AES128CBCDecrypt dec(&key[0], &iv[0], pad);
-    size = dec.Decrypt(&correctout[0], correctout.size(), &decrypted[0]);
+    AES128CBCDecrypt dec(key.data(), iv.data(), pad);
+    size = dec.Decrypt(correctout.data(), correctout.size(), decrypted.data());
     decrypted.resize(size);
     BOOST_CHECK(decrypted.size() == in.size());
     BOOST_CHECK_MESSAGE(decrypted == in, HexStr(decrypted) + std::string(" != ") + hexin);
@@ -133,12 +133,12 @@ void TestAES128CBC(const std::string &hexkey, const std::string &hexiv, bool pad
     {
         std::vector<unsigned char> sub(i, in.end());
         std::vector<unsigned char> subout(sub.size() + AES_BLOCKSIZE);
-        int _size = enc.Encrypt(&sub[0], sub.size(), &subout[0]);
+        int _size = enc.Encrypt(sub.data(), sub.size(), subout.data());
         if (_size != 0)
         {
             subout.resize(_size);
             std::vector<unsigned char> subdecrypted(subout.size());
-            _size = dec.Decrypt(&subout[0], subout.size(), &subdecrypted[0]);
+            _size = dec.Decrypt(subout.data(), subout.size(), subdecrypted.data());
             subdecrypted.resize(_size);
             BOOST_CHECK(decrypted.size() == in.size());
             BOOST_CHECK_MESSAGE(subdecrypted == sub, HexStr(subdecrypted) + std::string(" != ") + HexStr(sub));
@@ -155,16 +155,16 @@ void TestAES256CBC(const std::string &hexkey, const std::string &hexiv, bool pad
     std::vector<unsigned char> realout(in.size() + AES_BLOCKSIZE);
 
     // Encrypt the plaintext and verify that it equals the cipher
-    AES256CBCEncrypt enc(&key[0], &iv[0], pad);
-    int size = enc.Encrypt(&in[0], in.size(), &realout[0]);
+    AES256CBCEncrypt enc(key.data(), iv.data(), pad);
+    int size = enc.Encrypt(in.data(), in.size(), realout.data());
     realout.resize(size);
     BOOST_CHECK(realout.size() == correctout.size());
     BOOST_CHECK_MESSAGE(realout == correctout, HexStr(realout) + std::string(" != ") + hexout);
 
     // Decrypt the cipher and verify that it equals the plaintext
     std::vector<unsigned char> decrypted(correctout.size());
-    AES256CBCDecrypt dec(&key[0], &iv[0], pad);
-    size = dec.Decrypt(&correctout[0], correctout.size(), &decrypted[0]);
+    AES256CBCDecrypt dec(key.data(), iv.data(), pad);
+    size = dec.Decrypt(correctout.data(), correctout.size(), decrypted.data());
     decrypted.resize(size);
     BOOST_CHECK(decrypted.size() == in.size());
     BOOST_CHECK_MESSAGE(decrypted == in, HexStr(decrypted) + std::string(" != ") + hexin);
@@ -174,12 +174,12 @@ void TestAES256CBC(const std::string &hexkey, const std::string &hexiv, bool pad
     {
         std::vector<unsigned char> sub(i, in.end());
         std::vector<unsigned char> subout(sub.size() + AES_BLOCKSIZE);
-        int _size = enc.Encrypt(&sub[0], sub.size(), &subout[0]);
+        int _size = enc.Encrypt(sub.data(), sub.size(), subout.data());
         if (_size != 0)
         {
             subout.resize(_size);
             std::vector<unsigned char> subdecrypted(subout.size());
-            _size = dec.Decrypt(&subout[0], subout.size(), &subdecrypted[0]);
+            _size = dec.Decrypt(subout.data(), subout.size(), subdecrypted.data());
             subdecrypted.resize(_size);
             BOOST_CHECK(decrypted.size() == in.size());
             BOOST_CHECK_MESSAGE(subdecrypted == sub, HexStr(subdecrypted) + std::string(" != ") + HexStr(sub));
diff --git a/src/test/getarg_tests.cpp b/src/test/getarg_tests.cpp
index 18a7e599333ba..40f0ecd5f16b9 100644
--- a/src/test/getarg_tests.cpp
+++ b/src/test/getarg_tests.cpp
@@ -27,7 +27,7 @@ static void ResetArgs(const std::string& strArg)
     for (std::string& s : vecArg)
         vecChar.push_back(s.c_str());
 
-    gArgs.ParseParameters(vecChar.size(), &vecChar[0]);
+    gArgs.ParseParameters(vecChar.size(), vecChar.data());
 }
 
 BOOST_AUTO_TEST_CASE(boolarg)
diff --git a/src/test/skiplist_tests.cpp b/src/test/skiplist_tests.cpp
index e3654e67ad629..164cbd873feab 100644
--- a/src/test/skiplist_tests.cpp
+++ b/src/test/skiplist_tests.cpp
@@ -39,7 +39,7 @@ BOOST_AUTO_TEST_CASE(skiplist_test)
 
         BOOST_CHECK(vIndex[SKIPLIST_LENGTH - 1].GetAncestor(from) == &vIndex[from]);
         BOOST_CHECK(vIndex[from].GetAncestor(to) == &vIndex[to]);
-        BOOST_CHECK(vIndex[from].GetAncestor(0) == &vIndex[0]);
+        BOOST_CHECK(vIndex[from].GetAncestor(0) == vIndex.data());
     }
 }
 
@@ -64,7 +64,7 @@ BOOST_AUTO_TEST_CASE(getlocator_test)
     for (unsigned int i=0; i<vBlocksSide.size(); i++) {
         vHashSide[i] = ArithToUint256(i + 50000 + (arith_uint256(1) << 128)); // Add 1<<128 to the hashes, so GetLow64() still returns the height.
         vBlocksSide[i].nHeight = i + 50000;
-        vBlocksSide[i].pprev = i ? &vBlocksSide[i - 1] : &vBlocksMain[49999];
+        vBlocksSide[i].pprev = i ? &vBlocksSide[i - 1] : (vBlocksMain.data()+49999);
         vBlocksSide[i].phashBlock = &vHashSide[i];
         vBlocksSide[i].BuildSkip();
         BOOST_CHECK_EQUAL((int)UintToArith256(vBlocksSide[i].GetBlockHash()).GetLow64(), vBlocksSide[i].nHeight);
diff --git a/src/test/test_bitcoin_fuzzy.cpp b/src/test/test_bitcoin_fuzzy.cpp
index de14251601377..50e4076d0716a 100644
--- a/src/test/test_bitcoin_fuzzy.cpp
+++ b/src/test/test_bitcoin_fuzzy.cpp
@@ -67,7 +67,7 @@ int do_fuzz()
     if (buffer.size() < sizeof(uint32_t)) return 0;
 
     uint32_t test_id = 0xffffffff;
-    memcpy(&test_id, &buffer[0], sizeof(uint32_t));
+    memcpy(&test_id, buffer.data(), sizeof(uint32_t));
     buffer.erase(buffer.begin(), buffer.begin() + sizeof(uint32_t));
 
     if (test_id >= TEST_ID_END) return 0;
diff --git a/src/uint256.cpp b/src/uint256.cpp
index c4c7b716fea38..736a0d4fe2f04 100644
--- a/src/uint256.cpp
+++ b/src/uint256.cpp
@@ -14,7 +14,7 @@ template <unsigned int BITS>
 base_blob<BITS>::base_blob(const std::vector<unsigned char>& vch)
 {
     assert(vch.size() == sizeof(data));
-    memcpy(data, &vch[0], sizeof(data));
+    memcpy(data, vch.data(), sizeof(data));
 }
 
 template <unsigned int BITS>
diff --git a/src/wallet/crypter.cpp b/src/wallet/crypter.cpp
index dcce88cedc7e1..8db3bfd69c3b1 100644
--- a/src/wallet/crypter.cpp
+++ b/src/wallet/crypter.cpp
@@ -27,8 +27,7 @@ int CCrypter::BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, cons
     CSHA512 di;
 
     di.Write((const unsigned char*)strKeyData.c_str(), strKeyData.size());
-    if(chSalt.size())
-        di.Write(&chSalt[0], chSalt.size());
+    di.Write(chSalt.data(), chSalt.size());
     di.Finalize(buf);
 
     for(int i = 0; i != count - 1; i++)
@@ -82,7 +81,7 @@ bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned
     vchCiphertext.resize(vchPlaintext.size() + AES_BLOCKSIZE);
 
     AES256CBCEncrypt enc(vchKey.data(), vchIV.data(), true);
-    size_t nLen = enc.Encrypt(&vchPlaintext[0], vchPlaintext.size(), &vchCiphertext[0]);
+    size_t nLen = enc.Encrypt(&vchPlaintext[0], vchPlaintext.size(), vchCiphertext.data());
     if(nLen < vchPlaintext.size())
         return false;
     vchCiphertext.resize(nLen);
@@ -101,7 +100,7 @@ bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingM
     vchPlaintext.resize(nLen);
 
     AES256CBCDecrypt dec(vchKey.data(), vchIV.data(), true);
-    nLen = dec.Decrypt(&vchCiphertext[0], vchCiphertext.size(), &vchPlaintext[0]);
+    nLen = dec.Decrypt(vchCiphertext.data(), vchCiphertext.size(), &vchPlaintext[0]);
     if(nLen == 0)
         return false;
     vchPlaintext.resize(nLen);
@@ -113,7 +112,7 @@ static bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMateri
 {
     CCrypter cKeyCrypter;
     std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
-    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
+    memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
     if(!cKeyCrypter.SetKey(vMasterKey, chIV))
         return false;
     return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
@@ -123,7 +122,7 @@ static bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<u
 {
     CCrypter cKeyCrypter;
     std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
-    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
+    memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
     if(!cKeyCrypter.SetKey(vMasterKey, chIV))
         return false;
     return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 637ca04e82e3e..1d79a9b90604b 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -614,7 +614,7 @@ UniValue signmessage(const JSONRPCRequest& request)
     if (!key.SignCompact(ss.GetHash(), vchSig))
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Sign failed");
 
-    return EncodeBase64(&vchSig[0], vchSig.size());
+    return EncodeBase64(vchSig.data(), vchSig.size());
 }
 
 UniValue getreceivedbyaddress(const JSONRPCRequest& request)
diff --git a/src/wallet/test/crypto_tests.cpp b/src/wallet/test/crypto_tests.cpp
index cbd74b6f960f4..f4dabc50c0352 100644
--- a/src/wallet/test/crypto_tests.cpp
+++ b/src/wallet/test/crypto_tests.cpp
@@ -80,7 +80,7 @@ BOOST_AUTO_TEST_CASE(passphrase) {
 
     std::string hash(GetRandHash().ToString());
     std::vector<unsigned char> vchSalt(8);
-    GetRandBytes(&vchSalt[0], vchSalt.size());
+    GetRandBytes(vchSalt.data(), vchSalt.size());
     uint32_t rounds = InsecureRand32();
     if (rounds > 30000)
         rounds = 30000;