问题描述
限时送ChatGPT账号..C++ Notes: Array Initialization 有一个很好的列表数组的初始化.我有一个
int array[100] = {-1};
期望它充满 -1 但它不是,只有第一个值是,其余是 0 与随机值的混合.
代码
int array[100] = {0};
工作正常并将每个元素设置为 0.
我在这里遗漏了什么.. 如果值不为零,就不能初始化它吗?
和 2:默认初始化(如上)是否比通常的遍历整个数组并赋值的循环快,还是做同样的事情?
解决方案使用您使用的语法,
int array[100] = {-1};
说将第一个元素设置为 -1
,其余的设置为 0
",因为所有省略的元素都设置为 0
.>
在 C++ 中,要将它们全部设置为 -1
,您可以使用类似 std::fill_n
(来自):
std::fill_n(array, 100, -1);
在便携式 C 中,您必须滚动自己的循环.有编译器扩展,或者你可以依赖实现定义的行为作为捷径(如果可以的话).
C++ Notes: Array Initialization has a nice list over initialization of arrays. I have a
int array[100] = {-1};
expecting it to be full with -1's but its not, only first value is and the rest are 0's mixed with random values.
The code
int array[100] = {0};
works just fine and sets each element to 0.
What am I missing here.. Can't one initialize it if the value isn't zero ?
And 2: Is the default initialization (as above) faster than the usual loop through the whole array and assign a value or does it do the same thing?
解决方案Using the syntax that you used,
int array[100] = {-1};
says "set the first element to -1
and the rest to 0
" since all omitted elements are set to 0
.
In C++, to set them all to -1
, you can use something like std::fill_n
(from <algorithm>
):
std::fill_n(array, 100, -1);
In portable C, you have to roll your own loop. There are compiler-extensions or you can depend on implementation-defined behavior as a shortcut if that's acceptable.
这篇关于将数组的所有元素初始化为 C++ 中的一个默认值?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
更多推荐
[db:关键词]
发布评论