c_cpp CPP-迭代器

Posted 2021-05-14

#include<bits/stdc++.h>
using namespace std;

int main(){
//===============( defining iterator )================
    vector<int> a={2,4,3,6,7,8};
    vector<int> :: iterator i;
    for(i=a.begin();i!=a.end();i++){
        cout<< *i<<" ";  // *i -> a[i] (dereferencing)
    }
    cout<<endl;

//===================( using auto )===================
    for(auto j=a.begin();j!=a.end();j++){
        cout<< *j<<" ";
    }
    cout<<endl;

//==================( i'th index element using itearaor )============
    cout<<"Element at 4th index is: "<< *(a.begin()+4)<<endl; // *(i)=a[i]
    cout<<"Last element: "<< *(a.begin()+a.size()-1)<<endl;

//===================( using "for each" in loops )==============
    for(auto z:a){  // for each element in a
        cout<<z<<" "; // z=a[i]
    }
    cout<<endl;

    return 0;
}