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What is the function of auto and &(x) ? (they work the same way in this snippet of code below)

vector<int> v{3,1,4,1,5,9}; for(int &x: v) cout<< x << ' ' ; cout<< '\n'; for(auto x: v) cout<< x << ' ';

25th Aug 2018, 2:42 PM
Tincture
1 Resposta
+ 8
The "auto" keyword was introduced in C++11 so that you don't have to write std::vector<std::pair<std::vector<int>, int>> and other lengthy types every time you need to iterate over it, or to declare one with initialization. The compiler would deduce what datatype the variable/object should be. There are limitations though: auto x = 5; // ok auto x; // error x = 5; As for &, it's used to tell the compiler that x is a reference of the original elements in v, not merely a temporary variable storing the values of elements in v. Altering x will alter the elements in v.
25th Aug 2018, 2:53 PM
Hatsy Rei
Hatsy Rei - avatar