Giúp em khắc phục lỗi ambiguous với!

> #include "stdafx.h"
> #include "iostream"
> #include "conio.h"
> #include "math.h"
> #include "stdio.h"
> using namespace std;

> //2 Khai bao kieu
> typedef unsigned int word;
> typedef unsigned char byte;
> typedef unsigned int mang[100];

> //2.1 Khai bao cau truc
> typedef unsigned struct PS {
> 	int tuso;
> 	int mauso;
> };
> //Ham nhap gia tri
> void nhapps(PS &a);
> //Ham in gia tri
> void inps(PS a);
> //Ham toi gian
> void toigian(PS &a);
> //Tim USCLN
> unsigned uscln(unsigned a, unsigned b);
> //Tinh tich 2 phan so
> PS nhanps(PS a, PS b);
> int main()
> {
> 	PS a, b, t;

> 	do
> 	{
> 		////a = b;
> 		//// Thao tac tren tung thanh phan nho tren cau truc
> 		////Nhap lieu cho tu so
> 		//cout << "Nhap tu so: ";
> 		//cin >> a.tuso;
> 		//do {
> 		//	cout << "Nhap mau so:";
> 		//	cin >> a.mauso;
> 		//} while (a.mauso == 0);
> 		cout << "Nhap phan so thu nhat: 
";
> 		nhapps(a);
> 		cout << "Nhap phan so thu hai:
";
> 		nhapps(b);
> 		t = nhanps(a, b);
> 		cout << "Phan so tich =";
> 		inps(t);
> 		cout << endl;

> 		cout << "Nhan ESC de thoat! ";
> 	} while (_getch() != 27);
> 	return 0;
> }
> //Ham nhap gia tri
> void nhapps(PS &a)
> cout << "Nhap tu so: ";
> cin >> a.tuso;
> do {
> 	cout << "Nhap mau so:";
> 	cin >> a.mauso;
> } while (a.mauso == 0);
> //Ham in gia tri
> void inps(PS a)
> {
> 	cout << a.tuso << "/" << a.mauso;
> }
> //Ham toi gian
> void toigian(PS &a) {
> 	unsigned u = uscln(a.tuso, a.mauso);
> 	a.tuso /= u;
> 	a.mauso /= u;
> }
> //Tim USCLN
> unsigned uscln(unsigned a, unsigned b) {
> 	if (!a && !b) return 0;//loi
> 	if (!b) return a; // b ==0
> 	unsigned r = a%b;
> 	while (r) {
> 		a = b;
> 		b = r;
> 		r = a%b;
> 	}
> 	return b;
> }
> //Tinh tich 2 phan so
> PS nhanps(PS a, PS b) {
> 	PS t;  // bien cuc bo chua tich ---> tra ve`
> 	t.tuso = a.tuso*b.tuso;
> 	t.mauso = a.mauso*b.mauso;
> 	toigian(t);  // toi gian phan so tich
> 	return t;
> }

em có thử xài mấy cách thông thường, hay copy paste lại vẫn bị