Question

我制作了一个可以容纳2个称为“ arr”的整数的数组，但是当我要求范围之外的值而不是收到错误时，我得到了一个实际值。实际上，当我在索引3的“ arr”索引中设置一个值，然后要求程序在该位置打印该值时，不仅我没有收到错误，而且程序还提供了我在那里设置的实际值。但是我从来没有为“ arr”重新分配内存空间，所以这怎么工作？

代码：

#include <stdio.h>
#include <stdlib.h>

int main(){
  int* arr = malloc(2 * sizeof(int));

  arr[0]=5;
  arr[1]=6;

  arr[3] = 70; //this should be a segfault, right?

  while(1){
    int index;
    printf("\n\nWhich number do you want?");
    scanf("%d", &index);
    int val = arr[index];
    printf("here is your number: %d", val);
  }
}

输出：

Which number do you want?0
here is your number: 5

Which number do you want?1
here is your number: 6

Which number do you want?2
here is your number: 0

Which number do you want?3
here is your number: 70

Which number do you want?4
here is your number: 0

我不在为此数组分配的内存中，所以此段错误不应该吗？

0 个答案: