所以我需要能够一个接一个地拉出多个项目，无论出于何种原因，第二个＆＃34; .on＆＃34;从不执行。我有一个永远不会打印的console.log。
代码如下
#include<iostream>
#include<cstring>
#include<fstream>
using namespace std;
class student{
public:
virtual void read()=0;
virtual void display()=0;
virtual void write_student()=0;
virtual void c_eligibility(){}
virtual void show_student()=0;
};
class student_record:public student{
private:
int id;
string name;
string department;
string semester_name;
string grade;
float cgpa;
float gpa=0;
string subjects;
int f;
public:
void read(){}
void display(){}
void show_student(){}
void c_eligibility(){}
void write_student(){
cout<<"Enter students Name:";
cin>>name;
cout<<"Enter Students ID:";
cin>>id;
cout<<"Enter Students department:";
cin>>department;
cout<<"Please enter your semester name:";
cin>>semester_name;
cout<<"Please enter how many subjects you have taken:";
cin>>f;
cout<<"Please enter the subjects name and their Grade:"<<endl;
for(int i=1;i<=f;i++){
cout<<"Subject name:";
cin>>subjects;
cout<<"Grade=";
cin>>grade;
if(grade=="A"){
gpa=gpa+4.00;
}
else if(grade=="A-"){
gpa=gpa+3.70;
}
else if(grade=="B+"){
gpa=gpa+3.30;
}
else if(grade=="B"){
gpa=gpa+3.00;
}
else if(grade=="B-"){
gpa=gpa+2.70;
}
else if(grade=="C+"){
gpa=2.30;
}
else if(grade=="C"){
gpa=gpa+2.00;
}
else if(grade=="C-"){
gpa=gpa+1.70;
}
else if(grade=="D+"){
gpa=gpa+1.30;
}
else if(grade=="D"){
gpa=gpa+1.00;
}
else if(grade=="F"){
gpa=gpa+0.00;
}
cgpa=gpa/f;
}
cout<<"CGPA is:"<<cgpa<<endl;
ofstream out ("c:\\windows\\temp\\Student.txt",ios::app);
out << "Name = " <<name << endl;
out << "Id = " <<id << endl;
out << "Semester = " <<semester_name << endl;
out << "CGPA = " <<cgpa << endl;
out.close();
}
};
class student_show:public student{
private:
int id;
string name;
string department;
string semester_name;
string grade;
float cgpa;
public:
void read(){}
void display(){}
void write_student(){}
void c_eligibility(){}
void show_student(){
ifstream out;
out.open("c:\\windows\\temp\\Student.txt",ios::app);
out >>name;
out >>id;
out >>semester_name;
out >>cgpa;
cout << "Name = " <<name << endl;
cout << "Id = " <<id << endl;
cout << "Semester = " <<semester_name << endl;
cout << "CGPA = " <<cgpa << endl;
}
};
class eligibility:public student{
private:
float PHY,CHE,MAT;
int n,w,q;
public:
void read(){}
void display(){}
void show_student(){}
void write_student(){}
void c_eligibility(){
cout<<"Please enter your mark of PHY, CHE, MAT:"<<endl;
cin>>PHY;
cin>>CHE;
cin>>MAT;
if(PHY>=80 && CHE>=80 && MAT>=80){
cout<<"Congratulation you are eligible for the CCNA course. If you want to register now please enter 1 or 2 to main menu"<<endl;
cin>>q;
if(q==1){
cout<<"There are only " <<ticketLeft3() <<" seats available press 1 to confirm the advanced booking"<<endl;
cin>>w;
if(w==1){
ticketCounter3(w);
cout<<"Thank you for the confirmation";
}
}
}
else
cout<<"Please retake the subjects to have the required marks.";
}
int ticketCounter3( int x ){
int a;
a=ticketLeft3()-x;
ofstream in ("c:\\windows\\temp\\booking.txt");
in <<a;
}
int ticketLeft3()
{
int k;
ifstream out;
out.open("c:\\windows\\temp\\booking.txt");
out >>k;
return k;
}
};
int main()
{
student* s;
int n;
char ch;
while(n!=4)
{
cout<<"\tWelcome to Student Record System"<<endl<<endl;
cout<<"\t==================================================";
cout<<"\n\n\t1.Create Student Record";
cout<<"\n\n\t2.Display Student Record";
cout<<"\n\n\t3.CCNA Course Eligibility";
cout<<"\n\n\t==================================================";
cout<<"\n\n\tPlease Enter Your Choice (1-3) or 4 to exit: ";
cin>>n;
if(n==1){
s = new student_record;
s->write_student();
}
else if(n==2){
s = new student_show;
s-> show_student();
}
else if(n==3){
s=new eligibility;
s->c_eligibility();
}
}
return 0;
}
为什么第二个.once会失败？永远不会打印输入。
答案 0 :(得分：0)
找到了解决方法。使用
$scope.returnedObj = $firebaseObject(ref);
$scope.returnedObj.$loaded().then(function () {...})