C :

#include <stdio.h>
int main(void)
{
	char a[10],p[20];
	int s;
	scanf("%s",&a);
	while(1) 
	{
		getchar();
		scanf("%d",&s);
		if (s==123456)
		{
			printf("Hello %s\n",a);
			break;
		}
		else if (s==0)
		{
			printf("Wrong Password!");
			break;
		}
		else
		{
			printf("Wrong Password!\n");
		}
	}

	return 0;
}

C++ :

#include<iostream>
#include<string>
using namespace std;
int main()
{
	string name,pword;
	getline(cin,name);
	bool flag=false;
	do
	{
		getline(cin,pword);
		if (pword=="123456")
		{
			flag=true;
			cout<<"Hello "<<name<<endl;
			return 0;
		}
		else if (pword=="0")
		{
			cout<<"Wrong Password!"<<endl;
			return 0;
		}
		else cout<<"Wrong Password!"<<endl;
	} while (!flag);
}