BT22/GT LTCB A/TR.62

#include 
#include 



main(){
float a,tb=0,k=0;
printf("Nhap day so thuc ket thuc bang -1 \n(Moi so thuc phan biet voi nhau bang phim Enter):\n" );
scanf("%f",&a);fflush(stdin);

while(a!=-1){
 tb=tb+a;
 k++;
 scanf("%f",&a);
 fflush(stdin);
}
printf("Gia tri trung binh: %.2f",tb/k); 

getch();
}