integer indexed with a string in c++
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In C arrays why is this true? a[5] == 5[a]
How is it possible that this is valid C++?
void main()
{
int x = 1["WTF?"];
}
On VC++10 this compiles and in debug mode the value of x is 84 after the statement.
What's going on?
Array subscript operator is commutative. It's equivalent to int x = "WTF?"[1]; Here, "WTF?" is an array of 5 char s (it includes null terminator), and [1] gives us the second char, which is 'T' - implicitly converted to int it gives value 84.
Offtopic: The code snippet isn't valid C++, actually - main must return int .
You can read more in-depth discussion here: In C arrays why is this true? a[5] == 5[a]
int x = 1["WTF?"];
equals to
int x = "WTF?"[1];
84 is "T" ascii code
The reason why this works is that when the built-in operator [] is applied to a pointer and an int, a[b] is equivalent to *(a+b) . Which (addition being commutative) is equivalent to *(b+a) , which, by definition of [] , is equivalent to b[a] .
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