Question

When should we use vectors and when to use normal arrays. Also in one of my codes i found a weird problem.

 class TwoTrains   
   {  
          public:  
          int pass(int t1, int t2, vector <int>);  
   };

int TwoTrains::pass(int t1, int t2, vector <int> times)  
     {  
         int size_of_array=(int)times.size();  
         for(int i=0;i<size_of_array;i++)  
         {  
              cout<<times[i]<<endl;  
         }  
         return 0;  
     }  

This Compiles but when i use this it gives an error.Why –

 for(int i=0; i< times.size();i++)    

Answer 1

vector is what you want. Give arrays for plain-C users.

for(int i=0; i< times.size();i++)    

Gives no errors, but warning (Comparing signed with unsigned ). Use

for(size_t i=0; i< times.size();i++)  

or

for(int i=0; i<(int) times.size();i++)  

As you don’t need indexes, use iterators, as 0A0D notice:

for(vector<int>::iterator it = times.begin(); it!=times.end();++it){
    cout<<*it;
}

or even

for(int t: times){
    cout<<t;
}

with C++11