请问这个简单问题哪里有错误?
#include <iostream>
int sanjiaomianji(int leng,int with);
int main()
{
int di;
int gao;
int area;
std::cout<<"\n输入底为多少? ";
std::cin>>di;
std::cout<<"\n输入高为多少? ";
std::cin>>gao;
area=sanjiaomianji(di,gao);
std::cout<<"\n 面积是 ";
std::cout<<area;
return 0;
}
int sanjiaomianji(int d,int g);
{
return (d * g)/2;
}