C + + array subscript can be negative

We know that the first element of an array is subscript 0. The range of the array is from array[0] to array[size–1]. In fact, C + + supports positive and negative subscripts. The negative subscript must be within the bounds of the array, otherwise the result is unpredictable. The following code shows the positive and negative group subscripts:

#include <iostream>using namespace Std;int main () {    int intarray[1024];    for (int i = 0, j = 0; i < 1024x768; i++)    {        Intarray[i] = j + +;    }    cout << intarray[512] << Endl;    *midarray int = &intArray[512];  Points to the middle of the array data    cout << midarray[-256] << Endl;    cout << intarray[-256] << Endl;  To get unpredictable results}

A negative subscript in the last line can produce a run-time error because it points to an address that is 256 bytes lower in memory than the origin of the array. The pointer Midarray is initialized to the midpoint of the intarray, so you can use positive and negative group indexes on it. Array subscript errors do not produce compile-time errors, but they produce unpredictable results.

Reference: http://blog.csdn.net/mycwq/article/details/43373965

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C + + array subscript can be negative