这个程序哪错了

[zsdaqwa]

#include<iostream>
const double gllon=0.2513225;
double route_ave(double gas,double gak);
int main()
{
     using namespace std;
     double gas,gak,ave_route;
     char a;
     do 
     {
      cout<<"输入汽车消耗的油量：";
      cin>>gas;
      cout<<"输入行使的路程：";
      cin>>gak;
      ave_route=route_ave(gas,gak);
      cout<<ave_route;
      cin>>a;
     }
     while(a=='y'||a=='Y')
     return 0;  
}
double route_ave(double gas,double gak)
{
       gas=(gas/gak);
       return(gas*gllon);
} 

[hcon_1755]

while(a=='y'||a=='Y')
后面你少了个";" 习惯问题....