Array out of bounds causes a dead loop

<span style= "font-family:arial, Helvetica, Sans-serif; font-size:12px; " > #include <stdio.h></span>

int main () {    int i;    int a[5];        for (i = 0; I <= 5; i++) {        a[i] = 0;        A[i] =-I.;     The main is finally given a value smaller than 5 can be        printf ("%d  %d\n", I,a[i]);    }    return 0;}

A variable is passed in as a function parameter, but after the function call is finished , the value of the variable has changed, do not know why. It turns out that there is an address cross-border problem in the function, which causes the value of the variable to be changed, a bit incredible! For example, the following program, because the array subscript out of bounds causes a dead loop:

originally a simple array subscript out-of-bounds resulted in a dead loop, mainly due to compiler address space allocation.
in-memory addresses are assigned as follows:

High Address | i | a[4] | a[3] | a[2] | a[1] | a[0] | low address

The array address gradually increases, and the value of I is changed just beyond the bounds.
Although some compilers have optimized the memory gap between the array and I, if I cross the boundary seriously, such as accidentally giving 50, it will lead to a dead loop.


The above is in GCC (optimized), but in some gcc it is optimized. VC has been tested, but the operation will be an error in the process.

Array out of bounds causes a dead loop