Register - Login using Functions and String Functions

#include<stdio.h>
#include<string.h>
void Reg();
void Login();
void Profile();
char fname[30],lname[30],phone[10],addr[20],u1[10],u2[10],p1[10],p2[10];
void Reg()
{
// user registration
printf("Enter 1st name:");
scanf("%s",&fname);
printf("Enter last name:");
scanf("%s",&lname);
printf("Enter phone Number:");
scanf("%s",&phone);
printf("Enter address:");
scanf("%s",&addr);
printf("Create your user name:");
scanf("%s",&u1);
printf("Create your password:");
scanf("%s",&p1);
system("cls");
printf("Registration success");
Sleep(1000);
system("cls");
Login();
}
void Profile()
{
printf("Hai.. %s\n",u1);
strcat(fname," ");
printf("Full name:%s\n",strcat(fname,lname));
printf("Address:%s",addr);
}
void Login()
{
//user Login
printf("Enter user name:");
scanf("%s",&u2);
printf("Enter password:");
scanf("%s",&p2);
if(strcmp(u1,u2)==0&&strcmp(p1,p2)==0)
{
Profile();
}
else
{
printf("Invalid user name or password");
}
}


main()
{
Reg();
}