写文件如下

#include <iostream>
#include <Windows.h>

typedef HANDLE(WINAPI* CreateFileAFunc)(LPCSTR, DWORD, DWORD, LPSECURITY_ATTRIBUTES, DWORD, DWORD, HANDLE);

DWORD MyGetProcAddress(
	_In_ HMODULE hModule,
	_In_ LPCSTR lpProcName
)

{
	PIMAGE_DOS_HEADER pIMAGE_DOS_HEADER = (PIMAGE_DOS_HEADER)hModule;
	PIMAGE_NT_HEADERS pIMAGE_NT_HEADERS = (PIMAGE_NT_HEADERS)(pIMAGE_DOS_HEADER->e_lfanew + (DWORD)hModule);   //NT头
	PIMAGE_EXPORT_DIRECTORY pIMAGE_EXPORT_DIRECTORYRVA = (PIMAGE_EXPORT_DIRECTORY)(pIMAGE_NT_HEADERS->OptionalHeader.DataDirectory[0].VirtualAddress);  //导出表项，获得RVA  RVA并不是真正的导出表项需要转VA，转VA需要加上image_base(也就是加载地址）

	PIMAGE_EXPORT_DIRECTORY pIMAGE_EXPORT_DIRECTORY = (PIMAGE_EXPORT_DIRECTORY)((DWORD)pIMAGE_EXPORT_DIRECTORYRVA + (DWORD)hModule);  //这个才是真正的VA，真正的导出表项，因为RVA在内存中是没有的

	DWORD ModuleName = pIMAGE_EXPORT_DIRECTORY->Name + (DWORD)hModule;
	//可以看到底下地址都需要写成指针形式
	DWORD* pAddressOfFunction = (DWORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfFunctions + (DWORD)hModule);
	//printf("%s", ModuleName);
	DWORD* NameAddress = (DWORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfNames + (DWORD)hModule);
	WORD* pAddressOfNameOrdinals = (WORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfNameOrdinals + (DWORD)hModule);



	for (size_t i = 0; i < pIMAGE_EXPORT_DIRECTORY->NumberOfNames; i++)
	{
		DWORD FunNameRVA = NameAddress[i];
		char* FunName = (char*)(FunNameRVA + (DWORD)hModule);
		if (strcmp(lpProcName, FunName) == 0)
		{
			return (pAddressOfFunction[pAddressOfNameOrdinals[i]] + (DWORD)hModule);
		}
		printf("%s\n", FunName);
	}
	printf("%s\n", ModuleName);
	return NULL;
}
int main()
{
    std::cout << "Hello World!\n";
    // 加载 Kernel32.dll
    HMODULE hModule = LoadLibraryA("Kernel32.dll");
    if (hModule == NULL) {
        printf("Failed to load Kernel32.dll\n");
        return 1;
    }

    // 获取 CreateFileA 函数地址
    DWORD p1 = MyGetProcAddress(hModule, "CreateFileA");
    if (p1 == 0) {
        printf("Failed to get address of CreateFileA\n");
        return 1;
    }

    // 创建函数指针
    CreateFileAFunc pCreateFileA = (CreateFileAFunc)p1;




    DWORD dwBytesWritten;
    const char* lpFileName = "E:\\myfile.txt";
    const char* lpData = "Hello, World!";
    DWORD dwDataSize = strlen(lpData);
    // 调用 CreateFileA 函数

    HANDLE hFile = pCreateFileA(lpFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile != INVALID_HANDLE_VALUE) {
        // 写入文件内容
        if (WriteFile(hFile, lpData, dwDataSize, &dwBytesWritten, NULL)) {
            printf("文件写入成功！\n");
        }
        else {
            printf("写入文件时发生错误！\n");
        }
        // 关闭文件句柄
        CloseHandle(hFile);
    }
    else
    {
        printf("创建文件时发生错误！\n");
    }


    return 0;
}

读文件如下

#include <iostream>
#include <Windows.h>

typedef HANDLE(WINAPI* CreateFileAFunc)(LPCSTR, DWORD, DWORD, LPSECURITY_ATTRIBUTES, DWORD, DWORD, HANDLE);

DWORD MyGetProcAddress(
	_In_ HMODULE hModule,
	_In_ LPCSTR lpProcName
)

{
	PIMAGE_DOS_HEADER pIMAGE_DOS_HEADER = (PIMAGE_DOS_HEADER)hModule;
	PIMAGE_NT_HEADERS pIMAGE_NT_HEADERS = (PIMAGE_NT_HEADERS)(pIMAGE_DOS_HEADER->e_lfanew + (DWORD)hModule);   //NT头
	PIMAGE_EXPORT_DIRECTORY pIMAGE_EXPORT_DIRECTORYRVA = (PIMAGE_EXPORT_DIRECTORY)(pIMAGE_NT_HEADERS->OptionalHeader.DataDirectory[0].VirtualAddress);  //导出表项，获得RVA  RVA并不是真正的导出表项需要转VA，转VA需要加上image_base(也就是加载地址）

	PIMAGE_EXPORT_DIRECTORY pIMAGE_EXPORT_DIRECTORY = (PIMAGE_EXPORT_DIRECTORY)((DWORD)pIMAGE_EXPORT_DIRECTORYRVA + (DWORD)hModule);  //这个才是真正的VA，真正的导出表项，因为RVA在内存中是没有的

	DWORD ModuleName = pIMAGE_EXPORT_DIRECTORY->Name + (DWORD)hModule;
	//可以看到底下地址都需要写成指针形式
	DWORD* pAddressOfFunction = (DWORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfFunctions + (DWORD)hModule);
	//printf("%s", ModuleName);
	DWORD* NameAddress = (DWORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfNames + (DWORD)hModule);
	WORD* pAddressOfNameOrdinals = (WORD*)(pIMAGE_EXPORT_DIRECTORY->AddressOfNameOrdinals + (DWORD)hModule);



	for (size_t i = 0; i < pIMAGE_EXPORT_DIRECTORY->NumberOfNames; i++)
	{
		DWORD FunNameRVA = NameAddress[i];
		char* FunName = (char*)(FunNameRVA + (DWORD)hModule);
		if (strcmp(lpProcName, FunName) == 0)
		{
			return (pAddressOfFunction[pAddressOfNameOrdinals[i]] + (DWORD)hModule);
		}
		printf("%s\n", FunName);
	}
	printf("%s\n", ModuleName);
	return NULL;
}
int main()
{
    std::cout << "Hello World!\n";
    // 加载 Kernel32.dll
    HMODULE hModule = LoadLibraryA("Kernel32.dll");
    if (hModule == NULL) {
        printf("Failed to load Kernel32.dll\n");
        return 1;
    }

    // 获取 CreateFileA 函数地址
    DWORD p1 = MyGetProcAddress(hModule, "CreateFileA");
    if (p1 == 0) {
        printf("Failed to get address of CreateFileA\n");
        return 1;
    }

    // 创建函数指针
    CreateFileAFunc pCreateFileA = (CreateFileAFunc)p1;





    DWORD dwBytesRead;
    const char* lpFileName = "E:\\myfile.txt";
    const int BUFFER_SIZE = 1024;
    char buffer[BUFFER_SIZE];
    // 调用 CreateFileA 函数

    HANDLE hFile = pCreateFileA(lpFileName, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile != INVALID_HANDLE_VALUE) {
        // 读取文件内容
        if (ReadFile(hFile, buffer, BUFFER_SIZE - 1, &dwBytesRead, NULL)) {
            buffer[dwBytesRead] = '\0';  // 添加字符串结束符
            printf("文件内容：\n%s\n", buffer);
        }
        else {
            printf("写入文件时发生错误！\n");
        }
        // 关闭文件句柄
        CloseHandle(hFile);
    }
    else
    {
        printf("创建文件时发生错误！\n");
    }


    return 0;
}