Can anyone hep me fix this issue. I am a beginner and I get this error: identifier "I" is undefined

  1  #include<iostream>
  2  #include<fstream>
  3  using namespace std;
  4  class cars{
  5          public:
  6          string make;
  7          string model;
  8          int year;
  9          bool transmission;
 10          int price;
 11          void display()
 12          {
 13                  cout<<"Make "<<make<<endl;
 14                  cout<<"Model "<<model<<endl;
 15                  cout<<"year "<<year<<endl;
 16                  if(transmission)
 17                  cout<<"transmission "<<"Mannual"<<endl;
 18                  else
 19                  cout<<"transmission "<<"Automatic"<<endl;
 20                  cout<<"price "<<price<<endl;
 21          }
 22          
 23  };
 24  int main()
 25  {
 26          cars arr[3];
 27          ofstream filin;
 28          for(int i=0;i<3;i++)
 29          {
 30                  cout<<"Enter the details of car "<< i+1<<endl;
 31                  cout<<"enter make of car"<<endl;
 32                  cin>>arr[i].make;
 33                  cout<<"enter model of car"<<endl;
 34                  cin>>arr[i].model;
 35                  cout<<"enter year of car"<<endl;
 36                  cin>>arr[i].year;
 37                  cout<<"enter transmission of car"<<endl;
 38                  cout<<"1. Mannual"<<endl;
 39                  cout<<"2. Automatic"<<endl;
 40                  int t;
 41                  cin>>t;
 42                  if(t==1)arr[i].transmission=true;
 43                  else arr[i].transmission=false;
 44                  cout<<"enter price of car"<<endl;
 45                  cin>>arr[i].price;
 46          }
 47          cout<<"1. See car details"<<endl;
 48          cout<<"2. Update car details"<<endl;
 49          cout<<"3. print all car details"<<endl;
 50          cout<<"4. Save cars"<<endl;
 51          int q;
 52          cin>>q;
 53          if(q==1)
 54          {
 55                  cout<<"Enter number of car to search 1 or 2 or 3"<<endl;
 56                  int model1;
 57                  cin>>model1;
 58                  if(model1<3)
 59                  arr[model1-1].display();// 0 based indexing
 60                  else 
 61                  cout<<"Wrong number"<<endl;
 62          }
 63          if(q==2)
 64          {
 65                  cout<<"Enter number of car to update 1 or 2 or 3"<<endl;
 66                  int model1;
 67                  cin>>model1;
 68                  model1--; // 0 based indexing
 69                  cout<<"enter make of car"<<endl;
 70                  cin>>arr[model1].make;
 71                  cout<<"enter model of car"<<endl;
 72                  cin>>arr[model1].model;
 73                  cout<<"enter year of car"<<endl;
 74                  cin>>arr[i].year;
 75                  cout<<"enter transmission of car"<<endl;
 76                  cout<<"1. Mannual"<<endl;
 77                  cout<<"2. Automatic"<<endl;
 78                  int t;
 79                  cin>>t;
 80                  if(t==1)arr[i].transmission=true;
 81                  else arr[i].transmission=false;
 82                  cout<<"enter price of car"<<endl;
 83                  cin>>arr[i].price;
 84          }
 85          cout<<"1. See car details"<<endl;
 86          cout<<"2. Update car details"<<endl;
 87          cout<<"3. print all car details"<<endl;
 88          cout<<"4. Save cars"<<endl;
 89       
 90          cin>>q;
 91          if(q==1)
 92          {
 93                  cout<<"Enter number of car to search 1 or 2 or 3"<<endl;
 94                  int model1;
 95                  cin>>model1;
 96                  if(model1<3)
 97                  arr[model1-1].display();// 0 based indexing
 98                  else 
 99                  cout<<"Wrong number"<<endl;
100          }
101          if(q==2)
102          {
103                  cout<<"Enter number of car to update 1 or 2 or 3"<<endl;
104                  int model1;
105                  cin>>model1;
106                  model1--; // 0 based indexing
107                  cout<<"enter make of car"<<endl;
108                  cin>>arr[model1].make;
109                  cout<<"enter model of car"<<endl;
110                  cin>>arr[model1].model;
111                  cout<<"enter year of car"<<endl;
112                  cin>>arr[model1].year;
113                  cout<<"enter transmission of car"<<endl;
114                  cout<<"1. Mannual"<<endl;
115                  cout<<"2. Automatic"<<endl;
116                  int t;
117                  cin>>t;
118                  if(t==1)arr[model1].transmission=true;
119                  else arr[model1].transmission=false;
120                  cout<<"enter price of car"<<endl;
121                  cin>>arr[model1].price;
122          }
123          if(q==3)
124          {
125                  for(int i=0;i<3;i++)
126                  {
127                          arr[i].display();
128                  }
129          }
130          else
131          {
132                  filin.open("text.txt", ios::app);
133                  for(int i=0;i<3;i++)
134                  {
135                          filin.write((char*)&arr[i], sizeof(arr[i]));// writing into file
136                  }
137                  filin.close();  
138          }
139  }

identifier "i" is undefined

cin>>arr[i].year;
              cout<<"enter transmission of car"<<endl;
              cout<<"1. Mannual"<<endl;