Formal and actual do not have assignment compatible data types (expecting datatype compatible with 'int' but found 'queue of int' instead)

SystemVerilog
1

Hi
I got the following error, but I don’t how to fix it, please help! Thanks

error message:
xrun: 20.09-s003: (c) Copyright 1995-2020 Cadence Design Systems, Inc.
twosum(nums,9,x[$]);
|
xmvlog: *E,TYCMPAT (testbench.sv,21|18): formal and actual do not have assignment compatible data types (expecting datatype compatible with ‘int’ but found ‘queue of int’ instead).
xmvlog: *W,NOTOPL: no top-level unit found, must have recursive instances.
xrun: *E,VLGERR: An error occurred during parsing. Review the log file for errors with the code *E and fix those identified problems to proceed. Exiting with code (status 1).
TOOL: xrun 20.09-s003: Exiting on Dec 25, 2020 at 02:57:41 EST (total: 00:00:00)

my code:

module tb;
  
  int x[$];
      
  task twosum(input int nums[$],target,output int a[$]);
    foreach(nums[i]) begin
      for(int j=i+1;j<nums.size();j++)begin
        if(nums[i]+nums[j]==target)begin
          a=a.push_back[i];
          a=a.push_back[j];
         end
      end
    end
  endtask

  initial begin
    static int nums[$] ={2,7,11,15}; 
    int x[$];
    twosum(nums,9,x[$]);
    $display("dispaly:index:%d",x); 
  end
endmodule
2

In reply to lucky002:

Hi,

While making the call to the task ‘twosum’, you can simply pass ‘x’ as the argument. No need to use [$]. Please try this.

Hope this helps.
Putta Satish

3

In reply to puttasatish:

In reply to lucky002:
Hi,
While making the call to the task ‘twosum’, you can simply pass ‘x’ as the argument. No need to use [$]. Please try this.
Hope this helps.
Putta Satish

Thanks for helping me solve the problem!
but when I just call the task twosum(nums,9,x); it cause more error,like following:
xmelab: *E,FNTTSK (./testbench.sv,11|22): Expecting a function name.
a=a.push_back[i];
|
xmelab: *E,FAABP1 (./testbench.sv,11|22): Task/function call, or property/sequence instance does not specify all required formal arguments.
a=a.push_back[i];
|
xmelab: *E,BIMFOR (./testbench.sv,11|22): The format for this built in method is: task void push_back(input element_t item);.
a=a.push_back[j];
|
xmelab: *E,FNTTSK (./testbench.sv,12|22): Expecting a function name.
a=a.push_back[j];
|
xmelab: *E,FAABP1 (./testbench.sv,12|22): Task/function call, or property/sequence instance does not specify all required formal arguments.
a=a.push_back[j];
|
xmelab: *E,BIMFOR (./testbench.sv,12|22): The format for this built in method is: task void push_back(input element_t item);.
xrun: *E,ELBERR: Error during elaboration (status 1), exiting.
TOOL: xrun 20.09-s003: Exiting on Dec 30, 2020 at 21:00:39 EST (total: 00:00:01)

4

In reply to lucky002:

Your code has many problems. The following compiles and runs, but I have no idea what you expect it to do.

module tb;
 
  int x[$];
 
  task twosum(input int nums[$],target,output int a[$]);
    foreach(nums[i]) begin
      for(int j=i+1;j<nums.size();j++)begin
        if(nums[i]+nums[j]==target)begin
          a.push_back(i); // compare this to what you wrote
          a.push_back(j);
         end
      end
    end
  endtask
 
  initial begin
    static int nums[$] ={2,7,11,15}; 
    int x[$];
    twosum(nums,9,x);  // x - is the entire array x[$] is the last element 
    $display("dispaly:index:%p",x); // need %p
  end
endmodule
5

In reply to dave_59:

Hi David:
Thank you so much for helping me fix the problem. it is just a practice problem by using system verilog.