Can anyone explain this....what is the output of this ...and explain logic n answer behind this?

Question

#include <iostream>
using namespace std;

int main() {
int array[]={10,20,30};
cout<<-2[array];
return 0;
}

Answer 1

Let me translate the lines inside main() to english :-

1) int array[]={10,20,30};
Create an array with name "array" and put elements {10,20,30} in it in from the begining.

2) cout<<-2[array];
which is similar as
cout<<-array[2];
Means get the element at 2nd index of array(which is 30 as index start from 0) and print it after inverting it's sign
Thus the output will be -30.

Answer 2

This is an alternative sytax for reading a value from an array.
The 2 in front of [array] in the cout line is actually the array index. The Typical syntax would be array[2].

The value at index 2 is 30. As there is a negative sign preceeding the call to the array, the negative is applied to the output, giving the final output as:
-30

I hope this helps.