#include <Windows.h>
#include <iostream>
#include <string>
using namespace std;
 
void add(string strMenuText, string strApplication);
void del(string strMenuText);
 
int main(){
    system("pause");
    return 0;
}
 
void add(string strMenuText, string strApplication){
    //添加右键菜单项"加密该文件"
    HKEY hresult;  
    long value;
    //string strRegKeyName = "我的加密";
    string strRegKeyName = strMenuText;
    string strRegKey = "*\\shell\\" + strRegKeyName;//if txt file, please use "txtfile\\shell\\用我的文本编辑程序打开"
    string strRegSubkey="*\\shell\\" + strRegKeyName + "\\command";
    //string strMenuText="加密该文件"; 
    //string strApplication="E:\\Desktop\\Use\\xsearch_CHS.exe %1";
    strApplication = strApplication + " %1";
 
    DWORD dwPos;  
    //创建“加密”子键,并设置右键菜单项的名称
    value=RegCreateKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegKey.c_str(),0,NULL,REG_OPTION_NON_VOLATILE,KEY_CREATE_SUB_KEY|KEY_ALL_ACCESS,NULL,&hresult,&dwPos);
    value=RegSetValueEx(hresult,NULL,0,REG_SZ,(BYTE*)(LPCTSTR)strMenuText.c_str(), strMenuText.length()); 
    
    //创建“command”子键,并设置关联的应用程序
    value=RegCreateKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegSubkey.c_str(),0,NULL,REG_OPTION_NON_VOLATILE,KEY_CREATE_SUB_KEY|KEY_ALL_ACCESS,NULL,&hresult,&dwPos);
    value=RegSetValueEx(hresult,NULL,0,REG_SZ,(const BYTE*)(LPCTSTR)strApplication.c_str(),strApplication.length());
 
    //关闭注册表
    ::RegCloseKey(hresult);
}
 
void del(string strMenuText){
    HKEY hKey;
    //string strRegKeyName = "我的加密";
    string strRegKeyName = strMenuText;
    string strRegKey="*\\shell\\" + strRegKeyName;  
    string strRegSubkey="*\\shell";  
    
    //打开父键
    long lRet=::RegOpenKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegKey.c_str(),0,KEY_READ,&hKey);  
    
    //删除“command”子键  
    ::RegDeleteKey(hKey,LPCTSTR("command"));  
    ::RegCloseKey(hKey);  
    
    lRet=::RegOpenKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegSubkey.c_str(),0,KEY_READ,&hKey);
    
    //删除“加密”子键  
    ::RegDeleteKey(hKey,LPCTSTR(strRegKeyName.c_str()));  
    ::RegCloseKey(hKey);
}

下面是一个比较完整的例子:

#include <Windows.h>
#include <iostream>
#include <string>
#include "CommDlg.h"
 
using namespace std;
 
bool add(string strMenuText, string strApplication);
bool del(string strMenuText);
string openDlg();
 
int main(){
    while(true){
        cin.clear();
        cin.sync();
        int m = 0;
        cout << "(1)添加桌面菜单项 (2)删除桌面菜单项 (3)退出:";
        cin >> m;
 
        if(m == 1){
            std::string name, path;
            cout << "请输入菜单名:";
            cin.clear();
            cin.sync();
            getline(cin,name);
            cout << "输入程序路径:";
            cin.clear();
            cin.sync();
            //getline(cin, path);
            path = openDlg();
            if(!add(name, path)){
                cout << "添加失败!请以管理员身份运行" << endl;
            }else{
                cout << "添加完成!右键点击任意文件看看" << endl;
            }
        }
        if(m == 2){
            std::string name;
            cout << "请输入菜单名:";
            cin.clear();
            cin.sync();
            cin >> name;
            if(!del(name)){
                cout << "删除失败!请以管理员身份运行" << endl;
            }else{
                cout << "删除成功!" << endl;
            }
        }
        if(m == 3){
            return 0;
        }
    }
    system("pause");
    return 0;
}
string openDlg(){
TCHAR szBuffer[MAX_PATH] = {0};   
OPENFILENAME ofn= {0};   
ofn.lStructSize = sizeof(ofn);   
ofn.hwndOwner = NULL;   
ofn.lpstrFilter = ("Exe文件(*.exe)\0*.exe\0所有文件(*.*)\0*.*\0");//要选择的文件后缀   
ofn.lpstrInitialDir =  ("C:\\Program Files");//默认的文件路径   
ofn.lpstrFile = szBuffer;//存放文件的缓冲区   
ofn.nMaxFile = sizeof(szBuffer)/sizeof(*szBuffer);   
ofn.nFilterIndex = 0;   
ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST | OFN_EXPLORER ;//标志如果是多选要加上OFN_ALLOWMULTISELECT  
BOOL bSel = GetOpenFileName(&ofn);   
return szBuffer;
}
bool add(string strMenuText, string strApplication){
    //添加右键菜单项"加密该文件"
    HKEY hresult;  
    long value;
    //string strRegKeyName = "我的加密";
    string strRegKeyName = strMenuText;
    string strRegKey = "*\\shell\\" + strRegKeyName;//if txt file, please use "txtfile\\shell\\用我的文本编辑程序打开"
    string strRegSubkey="*\\shell\\" + strRegKeyName + "\\command";
    //string strMenuText="加密该文件"; 
    //string strApplication="E:\\Desktop\\Use\\xsearch_CHS.exe %1";
    strApplication = strApplication + " %1";
    DWORD dwPos;  
    //创建“加密”子键,并设置右键菜单项的名称
    value=RegCreateKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegKey.c_str(),0,NULL,REG_OPTION_NON_VOLATILE,KEY_CREATE_SUB_KEY|KEY_ALL_ACCESS,NULL,&hresult,&dwPos);
    if(0 != value){
        return false;
    }
    
    value=RegSetValueEx(hresult,NULL,0,REG_SZ,(BYTE*)(LPCTSTR)strMenuText.c_str(), strMenuText.length()); 
        if(0 != value){
        return false;
    }
    //创建“command”子键,并设置关联的应用程序
    value=RegCreateKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegSubkey.c_str(),0,NULL,REG_OPTION_NON_VOLATILE,KEY_CREATE_SUB_KEY|KEY_ALL_ACCESS,NULL,&hresult,&dwPos);
    if(0 != value){
        return false;
    }
    
    value=RegSetValueEx(hresult,NULL,0,REG_SZ,(const BYTE*)(LPCTSTR)strApplication.c_str(),strApplication.length());
    if(0 != value){
        return false;
    }
    //关闭注册表
    ::RegCloseKey(hresult);
}
bool del(string strMenuText){
    HKEY hKey;
    //string strRegKeyName = "我的加密";
    string strRegKeyName = strMenuText;
    string strRegKey="*\\shell\\" + strRegKeyName;  
    string strRegSubkey="*\\shell";  
    
    //打开父键
    long lRet=::RegOpenKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegKey.c_str(),0,KEY_READ,&hKey);  
    if(0 != lRet){
        return false;
    }
    //删除“command”子键  
    lRet = ::RegDeleteKey(hKey,LPCTSTR("command"));  
    if(0 != lRet){
        return false;
    }
    ::RegCloseKey(hKey);  
    
    lRet=::RegOpenKeyEx(HKEY_CLASSES_ROOT,(LPSTR)(LPCSTR)strRegSubkey.c_str(),0,KEY_READ,&hKey);
    if(0 != lRet){
        return false;
    }
    //删除“加密”子键  
    lRet = ::RegDeleteKey(hKey,LPCTSTR(strRegKeyName.c_str()));  
    if(0 != lRet){
        return false;
    }
    ::RegCloseKey(hKey);
}