iterator in c 2b 2b

1// string::begin/end
2#include <iostream>
3#include <string>
4
5int main ()
6{
7  std::string str ("Test string");
8  for ( std::string::iterator it=str.begin(); it!=str.end(); ++it)
9    std::cout << *it << endl;
10  std::cout << '\n';
11
12  return 0;
13}

1//Iterator Pointer like Structore in c++ of STL
2#include <bits/stdc++.h>
3using namespace std;
4
5int main(){
6    vector<int> v = {1,2,3,4,5};
7    for(int i = 0; i<v.size(); i++){
8        cout<<v[i]<<" ";
9    }
10    cout<<endl;
11
12    vector<int> :: iterator it;
13    // it = v.begin();
14    // cout<<(*it+1)<<endl;
15
16    for(it = v.begin(); it !=v.end(); ++it){
17        cout<<(*it)<<endl;
18    }
19    cout<<endl;
20
21    vector<pair<int, int>> v_p = {{1,2},{3,4},{5,6}};
22    vector<pair<int ,int>> :: iterator iter;
23    for(iter = v_p.begin(); iter !=v_p.end(); ++iter){
24        cout<<(*iter).first<<" "<<(*iter).second<<endl;
25    }
26    cout<<endl;
27    for(iter = v_p.begin(); iter !=v_p.end(); ++iter){
28        cout<<(iter->first)<<" "<<(iter->second)<<endl;
29    }
30
31    return 0;
32}

1#include <tuple>
2#include <iostream>
3#include <boost/hana.hpp>
4#include <boost/hana/ext/std/tuple.hpp>
5
6struct Foo1 {
7    int foo() const { return 42; }
8};
9
10struct Foo2 {
11    int bar = 0;
12    int foo() { bar = 24; return bar; }
13};
14
15int main() {
16    using namespace std;
17    using boost::hana::for_each;
18
19    Foo1 foo1;
20    Foo2 foo2;
21
22    for_each(tie(foo1, foo2), [](auto &foo) {
23        cout << foo.foo() << endl;
24    });
25
26    cout << "foo2.bar after mutation: " << foo2.bar << endl;
27}
28

1vector<int>::iterator ptr;