我在尝试着
从 scene.txt 中读取，进行计算并写入 stage1.txt
然后从 stage1.txt 读取并写入 stage2.txt
最后，读取stage2.txt，写入stage3.txt；
1和2工作得很好。但是，我不太确定，为什么我不能做第三个？
我使用 freopen 重定向标准输入和标准输出，然后在从第 1 点移动到第 2 点之前，我关闭了标准输入和标准输出。然后再次将 freopen 与不同的文件一起使用。
我怀疑使用 stringstream 会导致问题，但不能自信地说。
freopen("scene.txt","r",stdin);
freopen("stage1.txt","w",stdout);
//works fine. writes to stage1.txt
fclose(stdin);
fclose(stdout);
freopen("stage1.txt","r",stdin);
freopen("stage2.txt","w",stdout);
string test;
while(getline(cin,test))
{
if(test=="")
{
cout<<endl;
continue;
}
point p(1);
stringstream s(test);
s>>p.matrix[0]>>p.matrix[1]>>p.matrix[2];
point res;
res=apply_transformation(v,p);
res.print();
}
//it also does read from stage1.txt and writes to stage2.txt
fclose(stdout);
fclose(stdin);
freopen("stage2.txt","r",stdin);
freopen("stage3.txt","w",stdout);
string test3;
while(getline(cin,test3))
{
cout<<"YES"<<endl; //never gets here. cant even read stage2.txt
if(test3=="")
{
cout<<endl;
continue;
}
point p(1);
stringstream s(test3);
s>>p.matrix[0]>>p.matrix[1]>>p.matrix[2];
point res;
res=apply_transformation(P,p);
res.print();
cout<<p.matrix[0]<<" A "<<p.matrix[1]<<" "<<p.matrix[2]<<endl;
//cout<<test<<endl;
}
// above-mentioned loop doesn't work. cant read from stage2 and doesn't write anything to stage3.txt
我希望上面的第 3 点有效。但它没有。