update

CPP_Learn/CPP_Learn.cpp

@@ -1,6 +1,6 @@
 #include <iostream>
 
-int main()
+//int main()
-{
+//{
-    std::cout << "Hello World!\n";
+//    std::cout << "Hello World!\n";
-}
+//}

CPP_Learn/CPP_Learn.vcxproj

@@ -128,6 +128,7 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="CPP_Learn.cpp" />
+    <ClCompile Include="MemoryAlignment.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

CPP_Learn/CPP_Learn.vcxproj.filters

@@ -18,5 +18,8 @@
     <ClCompile Include="CPP_Learn.cpp">
       <Filter>源文件</Filter>
     </ClCompile>
+    <ClCompile Include="MemoryAlignment.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>

CPP_Learn/MemoryAlignment.cpp

@@ -0,0 +1,76 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+typedef struct {
+	int a;
+	int* p;
+	char c;
+	short s;
+	double d;
+	bool b;
+	short sArr[4];
+}struct1;
+
+typedef struct {
+	short sh;
+	struct1 s1;
+	char c;
+}struct2;
+
+typedef struct {
+	char c;
+	vector<int> vec;
+	short s;
+}struct3;
+
+void test() {
+	int i = 10;
+	struct1 s1 = {
+		1234,
+		&i,
+		'c',
+		123,
+		123.4,
+		true,
+		{1, 2, 3, 4}
+	};
+
+	cout << "size of struct1 : " << sizeof(s1) << endl;
+	cout << "offset of a : " << offsetof(struct1, a) << endl;
+	cout << "offset of p : " << offsetof(struct1, p) << endl;
+	cout << "offset of c : " << offsetof(struct1, c) << endl;
+	cout << "offset of s : " << offsetof(struct1, s) << endl;
+	cout << "offset of d : " << offsetof(struct1, d) << endl;
+	cout << "offset of b : " << offsetof(struct1, b) << endl;
+	cout << "offset of sArr : " << offsetof(struct1, sArr) << endl;
+	cout << "--------------" << endl << endl;
+
+	struct2 s2;
+	s2.sh = 42;
+	s2.c = 'f';
+
+	cout << "size of struct2 : " << sizeof(s2) << endl;
+	cout << "offset of s1 : " << offsetof(struct2, s1) << endl;
+	cout << "offset of c : " << offsetof(struct2, c) << endl;
+	cout << "--------------" << endl << endl;
+
+	struct3 s3;
+	s3.c = 'A';
+	s3.s = 678;
+	cout << "size of struct3 : " << sizeof(s3) << endl;
+	cout << "offset of c : " << offsetof(struct3, c) << endl;
+	cout << "offset of vec : " << offsetof(struct3, vec) << endl;
+	cout << "offset of s : " << offsetof(struct3, s) << endl;
+	cout << "--------------" << endl << endl;
+
+	for (int j = 0; j < 100; j++) {
+		s3.vec.push_back(j + 1);
+	}
+
+	cout << "done" << endl;
+}
+
+int main() {
+	test();
+}

CPP_Learn/x64/Debug/CPP_Learn.log

@@ -1,2 +1,2 @@
-  CPP_Learn.cpp
+  MemoryAlignment.cpp
   CPP_Learn.vcxproj -> E:\22020100011_LXB\Projects\VisualStudio\CPP_Learn\x64\Debug\CPP_Learn.exe