diff --git a/cpp/QrCode.cpp b/cpp/QrCode.cpp
index 4630752..faff7ae 100644
--- a/cpp/QrCode.cpp
+++ b/cpp/QrCode.cpp
@@ -96,8 +96,8 @@ QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, Ecc ecl,
 	// Concatenate all segments to create the data bit string
 	BitBuffer bb;
 	for (const QrSegment &seg : segs) {
-		bb.appendBits(seg.getMode().getModeBits(), 4);
-		bb.appendBits(seg.getNumChars(), seg.getMode().numCharCountBits(version));
+		bb.appendBits(static_cast<uint32_t>(seg.getMode().getModeBits()), 4);
+		bb.appendBits(static_cast<uint32_t>(seg.getNumChars()), seg.getMode().numCharCountBits(version));
 		bb.insert(bb.end(), seg.getData().begin(), seg.getData().end());
 	}
 	if (bb.size() != static_cast<unsigned int>(dataUsedBits))
diff --git a/cpp/QrCodeGeneratorDemo.cpp b/cpp/QrCodeGeneratorDemo.cpp
index 1286433..d8ee821 100644
--- a/cpp/QrCodeGeneratorDemo.cpp
+++ b/cpp/QrCodeGeneratorDemo.cpp
@@ -153,7 +153,7 @@ static void doSegmentDemo() {
 	};
 	qrcodegen::BitBuffer bb;
 	for (int c : kanjiChars)
-		bb.appendBits(c, 13);
+		bb.appendBits(static_cast<std::uint32_t>(c), 13);
 	const QrCode qr5 = QrCode::encodeSegments(
 		{QrSegment(QrSegment::Mode::KANJI, kanjiChars.size(), bb)},
 		QrCode::Ecc::LOW);
diff --git a/cpp/QrSegment.cpp b/cpp/QrSegment.cpp
index 64d77f7..a12f273 100644
--- a/cpp/QrSegment.cpp
+++ b/cpp/QrSegment.cpp
@@ -81,13 +81,13 @@ QrSegment QrSegment::makeNumeric(const char *digits) {
 		accumData = accumData * 10 + (c - '0');
 		accumCount++;
 		if (accumCount == 3) {
-			bb.appendBits(accumData, 10);
+			bb.appendBits(static_cast<uint32_t>(accumData), 10);
 			accumData = 0;
 			accumCount = 0;
 		}
 	}
 	if (accumCount > 0)  // 1 or 2 digits remaining
-		bb.appendBits(accumData, accumCount * 3 + 1);
+		bb.appendBits(static_cast<uint32_t>(accumData), accumCount * 3 + 1);
 	return QrSegment(Mode::NUMERIC, charCount, std::move(bb));
 }
 
@@ -104,13 +104,13 @@ QrSegment QrSegment::makeAlphanumeric(const char *text) {
 		accumData = accumData * 45 + (temp - ALPHANUMERIC_CHARSET);
 		accumCount++;
 		if (accumCount == 2) {
-			bb.appendBits(accumData, 11);
+			bb.appendBits(static_cast<uint32_t>(accumData), 11);
 			accumData = 0;
 			accumCount = 0;
 		}
 	}
 	if (accumCount > 0)  // 1 character remaining
-		bb.appendBits(accumData, 6);
+		bb.appendBits(static_cast<uint32_t>(accumData), 6);
 	return QrSegment(Mode::ALPHANUMERIC, charCount, std::move(bb));
 }
 
@@ -138,13 +138,13 @@ QrSegment QrSegment::makeEci(long assignVal) {
 	if (assignVal < 0)
 		throw std::domain_error("ECI assignment value out of range");
 	else if (assignVal < (1 << 7))
-		bb.appendBits(assignVal, 8);
+		bb.appendBits(static_cast<uint32_t>(assignVal), 8);
 	else if (assignVal < (1 << 14)) {
 		bb.appendBits(2, 2);
-		bb.appendBits(assignVal, 14);
+		bb.appendBits(static_cast<uint32_t>(assignVal), 14);
 	} else if (assignVal < 1000000L) {
 		bb.appendBits(6, 3);
-		bb.appendBits(assignVal, 21);
+		bb.appendBits(static_cast<uint32_t>(assignVal), 21);
 	} else
 		throw std::domain_error("ECI assignment value out of range");
 	return QrSegment(Mode::ECI, 0, std::move(bb));