I want to have a SystemVerilog class which contains an array of another class, like below:
class AggregateClass;
integer x;
OtherClass[x] otherClassArray;
extern function new(int x, logic in);
endclass: AggregateClass
class OtherClass;
// ...
extern function new(logic in);
// ...
endclass: OtherClass
How do I define an array of classes in SystemVerilog?
How can I have the number of class objects in said class array be set by the constructor?
When declaring a static array, you need a constant to declare its size; so, a variable cannot be used there. However, in SystemVerilog you can use dynamic arrays as follows:
class B;
int val;
function new(int v);
val = v;
endfunction
function void print;
$display("%0d", val);
endfunction
endclass
class A;
int x;
B b[int]; // << declaration of a dynamic array
function new(int n);
x = n;
for (int i = 0; i < n; i++)
b[i] = new(i); // <<< construction of dynamic array elements of class B.
endfunction
function void print;
$display("size: %0d", b.size);
for (int i = 0; i < x; i++)
b[i].print;
endfunction
endclass
module top;
initial begin
A a = new(4);
a.print();
end
endmodule
Related
I am new to OOP in C++. I got a doubt. I know it may be a silly doubt.
In the code below in main function, commented line will give error as I can not access private data memebers directly. but in the member function complex add(complex &C) I created a object temp of class complex. How can I access the data member of object temp directly and modify them as those are private. Like in the main function, should it not throw error? Is there any rule that in the member function of class we can access private data of a object of same class directly.
using namespace std;
class complex{
private:
int real;
int img;
public:
complex(int r = 0, int i = 0);
complex add(complex &C);
};
complex :: complex(int r, int i){
real = r;
img = i;
}
complex complex :: add(complex &C){
complex temp;
temp.real = real + C.real;
temp.img = img + C.img;
return temp;
}
int main() {
complex c1(3,4);
complex c2(5,7);
complex c3;
// c3.real = 3;
// c3.img = 5;
c3 = c1.add(c2);
return 0;
}
I try and stick to rule, keep your member variables private, if you need to change them or access them once the object is created, use a public get / set function.
e.g:
int complex::GetReal() const { return m_real; }
void complex::SetReal(const int i) { m_real = i; }
I have mocked a function which takes std::set (stl) as an argument and I expected it to be called with the right args. std::set is a set of user-defined struct and I just want to verify one field of that struct to have one value for all the member of the set.
ie
struct my_struct {
int i;
int j;
int k;
}
using my_set = std::set<my_struct>;
MOCK_METHOD(void, my_func, (my_set));
EXPECT_CALL(obj, my_func(_))
.Times(1);
Now I want to expect my_func to be called with my_set and each member of my_set is my_struct and my_struct.i should be 1 for all the members.
I understand it could be done with Matcher and Each but now sure how to do that as I run into compilation error
The key is to use ::testing::Each matcher with ::testing::Field matcher combined. Each iterates over all elements of the container argument and Field matcher allows you to set proper expectations on the user-defined struct fields. Complete example:
struct my_struct {
int i;
int j;
int k;
};
auto my_set_comp = [](const auto& l, const auto& r) { return std::tie(l.i, l.j, l.k) < std::tie(r.i, r.j, r.k); };
using my_set = std::set<my_struct, decltype(my_set_comp)>;
class MockClass {
public:
MOCK_METHOD(void, my_func, (my_set));
};
TEST(SetTest, test1) {
MockClass obj{};
my_set a_set{my_set_comp};
a_set.emplace(my_struct{1, 1, 1});
a_set.emplace(my_struct{1, 2, 2});
a_set.emplace(my_struct{1, 3, 3});
EXPECT_CALL(obj, my_func(::testing::Each(::testing::Field(&my_struct::i, 1)))).Times(1);
obj.my_func(a_set);
}
or here.
What is the importance of defining indegree vector in the private of a class? It could have been defined in alltopologicalSort() function.
class Graph
{
int V; // No. of vertices
// Pointer to an array containing adjacency list
list<int> *adj;
// Vector to store indegree of vertices
vector<int> indegree;
// A function used by alltopologicalSort
void alltopologicalSortUtil(vector<int>& res,
bool visited[]);
public:
Graph(int V); // Constructor
// function to add an edge to graph
void addEdge(int v, int w);
// Prints all Topological Sorts
void alltopologicalSort();
};
And how it is functioning in below addedge function
void Graph::addEdge(int v, int w)
{
adj[v].push_back(w); // Add w to v's list.
// increasing inner degree of w by 1
indegree[w]++;
}
Use of indegree, please explain here the role of addEdge function in decrementing indegree
void Graph::alltopologicalSortUtil(vector<int>& res,
bool visited[])
{
// To indicate whether all topological are found
// or not
bool flag = false;
for (int i = 0; i < V; i++)
{
// If indegree is 0 and not yet visited then
// only choose that vertex
if (indegree[i] == 0 && !visited[i])
{
// reducing indegree of adjacent vertices
list<int>:: iterator j;
for (j = adj[i].begin(); j != adj[i].end(); j++)
indegree[*j]--;
// including in result
res.push_back(i);
visited[i] = true;
alltopologicalSortUtil(res, visited);
// resetting visited, res and indegree for
// backtracking
visited[i] = false;
res.erase(res.end() - 1);
for (j = adj[i].begin(); j != adj[i].end(); j++)
indegree[*j]++;
flag = true;
}
}
}
This is the link to complete code of finding All Topological Sorts of Directed Acyclic Graph
https://www.geeksforgeeks.org/all-topological-sorts-of-a-directed-acyclic-graph/
I have got my answer from above discussion with Gupta and kaya3
Indegree could have been defined in some function and then passed to alltopologicalSort() function as a reference. But then defining it in class makes it easier to deal with.
And Data members of a class are always kept private because of encapsulation rules
I got this function
array<ItemType>^ GetNextItems(int n) {
auto ret = gcnew Collections::Generic::List < ItemType > ;
for (int i = 0; i < n; i++) {
auto item = GetNextItem();
if (item == ItemType()) break;
ret->Add(item);
}
return ret->ToArray();
}
But the compile gives me an error: cannot convert from 'cli::array< ItemType,1 > ^' to 'cli::array< ItemType,1 > ^'
ItemType is a template parameter ie.
generic <typename ItemType>
I've been staring at this for a while, I can't detect the fault. Why won't it compile?
If ItemType is a .NET/CLR type, then you'll need the ^-hat inside the return type declaration. The ^ is still not included in the actual type declaration.
So it would be something like this:
generic <typename ItemType>
ref class Test
{
array<ItemType ^>^
GetNextItems(int n)
{
List<ItemType ^> ^ ret = gcnew List<ItemType ^>(n);
...
return ret->ToArray();
}
};
Notice the added caret inside the <ItemType ^> return type declaration, but not in the class' generic definition.
probably there is a smart way to do that , but anyway i get error on this :
-(int*)decimalBinary:(int)decimal
{
int i=0;
int *bin;
while (decimal!=0)
{
bin[i]=decimal%2;
decimal=decimal/2;
i++;
}
return bin;
}
on the modulo line . why ?
And whats the better way to get it to array ?
Declaring
int *bin;
sets aside space for a pointer but doesn't make it point to an object. It is crucial to initialize bin before using it.
To solve your problem you can declare an array bin[4] in caller function (int main) and then pass *bin to your calling function.
The following code is adapted from This answer on how to print an integer in binary format. Storing "binary digits" into an int array is added into the code below:
#include <stdio.h> /* printf */
#include <stdlib.h> /* strtol */
const char *byte_to_binary(long x);
int main(void)
{
long lVal;
int i, len, array[18];
char buf[18];
{ /* binary string to int */
char *tmp;
char *b = "11010111001010110";
lVal=strtol(b, &tmp, 2); //convert string in "base 2" format to long int
printf("%d\n", lVal);
}
{
printf("%s", byte_to_binary(lVal));
/* byte to binary string */
sprintf(buf,"%s", byte_to_binary(lVal));
}
len = strlen(buf);
for(i=0;i<len;i++)
{ //store binary digits into an array.
array[i] = (buf[i]-'0');
}
getchar();
return 0;
}
const char *byte_to_binary(long x)
{
static char b[17]; //16 bits plus '\0'
b[0] = '\0';
char *p = b;
int z;
for (z = 65536; z > 0; z >>= 1) //2^16
{
*p++ = (x & z) ? '1' : '0';
}
return b;
}