如何从c中的数组中删除一系列元素 [英] how to remove a range of elements from an array in c

问题描述

我需要从数组中删除一系列元素，但是我不知道如何做。
我尝试了此for循环，其中start是范围的开始，而end是范围的结束。

I need to remove a range of elements from an array but I can't figure out how. I tried this for loop where start is that start of the range and end is the end of the range.

for (i=0;i<n;i++){
a1[start+i] = a1[end+i+1];;
}

推荐答案

从数组中删除一系列元素

to remove a range of elements from an array

在C中，一旦定义了 array ，元素范围是固定的。无法将其删除。 @hyde

In C, once an array is defined, the range of elements is fixed. They cannot be removed. @hyde

代码可以在运行时重新分配元素值。

Code can at run time, re-assign element values.

使用数组 [1,2,3,4,5,6,7] ，我们想删除 [ 3,4,5] ，然后以 [1,2,6,7，x，x，x] 结尾。这里 x 必须是一些值，也许是0。

With an array [1,2,3,4,5,6,7] and we want to "removed" [3,4,5] and then end up with [1,2,6,7, x, x, x]. Here x needs to be some value, perhaps 0.

size_t start;                              // Array index of sub-range beginning to "remove"
size_t end;                                // Array index of sub-range end to "remove"
size_t n = sizeof a1/sizeof a1[0];           // Number of elements in the array
assert(start < n && end < n && start <= end);// Make certain we have sane input    

size_t n_move = end - start + 1; // Number of elements to move 
memmove(&a1[start], &a1[end + 1], sizeof a1[0]*n_move);

size_t n_clear = n - end; // Number of elements to zero 
memset(&a1[end + 1], 0, sizeof a1[0]*n_clear);

---

OP代码对于 n ？

我希望循环迭代计数为 end-start + 1 。

sub_range_count = end - start + 1;
for (i=0; i<sub_range_count; i++){
  a1[start+i] = a1[end+i+1];;
}

这仍然使数组的后半部分保留原始值。

This still leaves the later part of the array with the original values.

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