sv push_back函数
时间: 2023-07-31 17:06:32 浏览: 80
`std::vector` 是 C++ 中的一个动态数组容器,它提供了 `push_back` 函数,可以向容器中添加一个新元素。
`push_back` 函数的用法如下:
```c++
void push_back( const T& value );
void push_back( T&& value );
```
其中,`T` 是容器中元素的类型,`value` 是要添加的元素。
使用 `push_back` 函数,可以在 `std::vector` 的末尾添加一个新元素。如果容器的大小已经达到了它的容量,`push_back` 函数会自动扩容。
例如,下面的代码演示了如何使用 `push_back` 函数向一个 `std::vector` 中添加元素:
```c++
#include <iostream>
#include <vector>
int main() {
std::vector<int> vec;
vec.push_back(1);
vec.push_back(2);
vec.push_back(3);
for (auto x : vec) {
std::cout << x << " ";
}
std::cout << std::endl;
return 0;
}
```
输出结果为:
```
1 2 3
```
相关问题
push_back sv
`push_back` and `sv` are both features in C++.
`push_back` is a method available on many standard C++ containers such as `std::vector`, `std::deque`, and `std::list`. It is used to add an element to the end of the container.
For example, if we have a vector of integers:
```
std::vector<int> vec {1, 2, 3};
```
We can add an additional element to the end using `push_back`:
```
vec.push_back(4);
```
Now the vector contains `{1, 2, 3, 4}`.
`sv` on the other hand, is a C++20 feature that stands for "string view". It is used to create a read-only view of a string without copying its contents.
For example, if we have a string:
```
std::string str = "hello world";
```
We can create a string view of the first 5 characters using `sv`:
```
std::string_view view = str.substr(0, 5);
```
Now `view` contains `"hello"`, but does not copy the contents of `str`. This can be useful for passing strings around without incurring the cost of copying them.
but if I remove the keyword packed as you suggested, vcs reports 2 errors: Error-[IBC] Invalid bounds count sc_assignment_pattern_030.sv,29 The following access has an invalid number of indices.st4.st2.push_back Error-[XMRE] Cross Module reference resolution error sc_assignment_pattern_030.sv, 29 Error found while trying to resolve cross-module reference. token 'st2'. Originating module 'test'. Source Info:st4.st2.push_back((i+1)); then how should I fix these 2 errors?
I apologize for the mistake in my previous answer. The use of an unpacked array in the struct declaration requires an explicit size. To fix the syntax error and the cross-module reference error, you can modify the declaration of `st2` to include a size for the unpacked array.
Here is the corrected code:
```
module test;
typedef struct packed {
logic [9:-1][2:0] a;
} ST1;
typedef struct {
ST1 st1;
ST1 st2[$];
logic [7:0] b;
} ST4;
initial begin
ST4 st4;
st4.st1.a[0][0] = 1;
for (int i = 0; i < 5; i++) begin
st4.st2.push_back(ST1'(i + 1));
end
st4.b = 8'hAA;
$display("%s", st4.st2); //CHECK-001:'{a:'h1}, st2:'{'a:'h1}, {'a:'h2},{'a:'h3},{'a:'h4},{'a:'h5}}}
end
endmodule
```
In this code, the declaration of `st2` now includes the size `[$]` to indicate that it is an unpacked array with a dynamic size. The `$` size specifier allows the size of the array to be determined at runtime, based on the number of elements that are pushed onto the array using the `push_back` method.
With this modification, the code should now compile without any syntax errors or cross-module reference errors.
相关推荐
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)