std::string str = “hello, world”;  
for(auto ch : str) {  
     std::cout << ch << std::endl;  
}  

int arr[] = {1, 2, 3, 4};  
for(auto i : arr) {  
     std::cout<< i << std::endl;  
} 

std::vector<std::string> str_vec = {“i”, “like”,  "google”};  
for(auto& it : str_vec) {  
     it = “c++”;  
}  

std::map<int, std::string> hash_map = {{1, “c++”}, {2, “java”}, {3, “python”}};  
for(auto it : hash_map) {  
     std::cout << it.first << “\t” << it.second << std::endl;  
}