だまってこれ使え
class FilePtr
{
public:
explicit FilePtr(const char* text,const char *wr){ pfile = std::fopen(text,wr) ; if(!pfile) throw int( 0 ); }
~ FilePtr() { if(pfile) std::fclose(pfile); }
operator std::FILE* () { return pfile ; }
private:
std::FILE* pfile;
};
int main(){
try{
FilePtr fptr("test.txt","r");
}
catch(int){
std::puts( "Non File" );
}

return 0;
}