Writing values into memory and reading those values. Timing Issue!!!

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And how is the mem defined? What is the memory code?

Why do you delay the read address on a read task?

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Memory is defined as logic [7:0] memory [0:31]

Please find the entire code below.

The memory module and test bench are instantiated in the top module.

****************** TOP MODULE ******************
module top;// SYSTEMVERILOG: timeunit and timeprecision specification
timeunit 1ns;
timeprecision 1ns;
// SYSTEMVERILOG: logic and bit data types
bit         clk;
wire       read;
wire       write;
wire  addr;
wire  data_out;      // data_from_mem
wire  data_in;       // data_to_mem
// SYSTEMVERILOG:: implicit .* port connections
mem_test test (.*);
// SYSTEMVERILOG:: implicit .name port connections
mem memory ( .clk, .read, .write, .addr,
              .data_in, .data_out
            );
always# 5 clk = ~clk;
endmodule

*********************** MEMORY MODULE ***********************
module mem (        input        clk,
	input        read,
	input        write, 
	input  logic  addr  ,
	input  logic  data_in  ,
        output logic  data_out
	   );
// SYSTEMVERILOG: timeunit and timeprecision specification
timeunit 1ns;
timeprecision 1ns;
// SYSTEMVERILOG: logic data type
logic  memory  ;
  
  always @(posedge clk)
    if (write && !read)
// SYSTEMVERILOG: time literals
       memory <= data_in;
// SYSTEMVERILOG: always_ff and iff event control
  always_ff @(posedge clk iff ((read == '1)&&(write == '0)) )
       data_out <= memory;
endmodule

Below is the output. I am writing "zero" in all the addresses and reading. You willbe seeing "x" once i start the reading process. That's the issue i am trying to fix.

**************************** OUTPUT ******************************
addr=00000, data_in=00000000                                                                                                                                                                                    
addr=00001, data_in=00000000                                                                                                                                                                                    
addr=00010, data_in=00000000                                                                                                                                                                                    
addr=00011, data_in=00000000                                                                                                                                                                                    
addr=00100, data_in=00000000                                                                                                                                                                                    
addr=00101, data_in=00000000                                                                                                                                                                                    
addr=00110, data_in=00000000                                                                                                                                                                                    
addr=00111, data_in=00000000                                                                                                                                                                                    
addr=01000, data_in=00000000                                                                                                                                                                                    
addr=01001, data_in=00000000                                                                                                                                                                                    
addr=01010, data_in=00000000                                                                                                                                                                                    
addr=01011, data_in=00000000                                                                                                                                                                                    
addr=01100, data_in=00000000                                                                                                                                                                                    
addr=01101, data_in=00000000                                                                                                                                                                                    
addr=01110, data_in=00000000                                                                                                                                                                                    
addr=01111, data_in=00000000                                                                                                                                                                                    
addr=10000, data_in=00000000                                                                                                                                                                                    
addr=10001, data_in=00000000                                                                                                                                                                                    
addr=10010, data_in=00000000                                                                                                                                                                                    
addr=10011, data_in=00000000                                                                                                                                                                                    
addr=10100, data_in=00000000                                                                                                                                                                                    
addr=10101, data_in=00000000                                                                                                                                                                                    
addr=10110, data_in=00000000                                                                                                                                                                                    
addr=10111, data_in=00000000                                                                                                                                                                                    
addr=11000, data_in=00000000                                                                                                                                                                                    
addr=11001, data_in=00000000                                                                                                                                                                                    
addr=11010, data_in=00000000                                                                                                                                                                                    
addr=11011, data_in=00000000                                                                                                                                                                                    
addr=11100, data_in=00000000                                                                                                                                                                                    
addr=11101, data_in=00000000                                                                                                                                                                                    
addr=11110, data_in=00000000                                                                                                                                                                                    
addr=11111, data_in=00000000                                                                                                                                                                                    
addr=00000, data_out=xxxxxxxx                                                                                                                                                                                   
addr=00001, data_out=00000000                                                                                                                                                                                   
addr=00010, data_out=00000000