How to assign value to b,plz....

[Sasi Cm]

module compare(a,out0,out1,out2,temp,temp1,temp2);
input [0:19]a;
wire [0:4]b;
output [0:1]out0,out1,out2;
reg [0:1]out0,out1,out2;
output [0:4] temp,temp1,temp2;
reg [0:4] temp,temp1,temp2;
always @(a)
begin
assign b[0:4]=a[0:4];
assign temp=b[0:4]^a[5:9];
if(temp[0]!=1&&temp[1]!=1&&temp[2]!=1&&temp[3]!=1&&temp[4]!=1)
begin
out0<=0;
end
else if(temp[0]!=0&&temp[1]!=0&&temp[2]!=0&&temp[3]!=0&&temp[4]!=0)
begin
out0<=10;
b[0:4]<=!a[0:4];
end
else
begin
out0<=11;
b[0:4]<=temp[0:4];
end

assign temp1=a[0:4]^a[10:14];
if(temp1[0]!=1&&temp1[1]!=1&&temp1[2]!=1&&temp1[3]!=1&&temp1[4]!=1)
begin
out1<=0;
end
else if(temp1[0]!=0&&temp1[1]!=0&&temp1[2]!=0&&temp1[3]!=0&&temp1[4]!=0)
begin
out1<=10;
b[0:4]<=!b[0:4];
end
else
begin
out1<=11
b[0:4]<=temp1[0:4];
end

assign temp2=a[0:4]^a[15:19];
if(temp2[0]!=1&&temp2[1]!=1&&temp2[2]!=1&&temp2[3]!=1&&temp2[4]!=1)
begin
out2<=0;
end
else if(temp2[0]!=0&&temp2[1]!=0&&temp2[2]!=0&&temp2[3]!=0&&temp2[4]!=0)
begin
out2<=10;
b[0:4]<=!b[0:4];
end
else
begin
out2<=11
b[0:4]<=temp2[0:4];
end

end
endmodule

I dont know to assign value to b..,Help me to overcome the error....

 

[aruipksni]

module compare(a,out0,out1,out2,temp,temp1,temp2);
input [0:19]a;
wire [0:4]b;
output [0:1]out0,out1,out2;
reg [0:1]out0,out1,out2;
output [0:4] temp,temp1,temp2;
reg [0:4] temp,temp1,temp2;
always @(a)
begin
assign b[0:4]=a[0:4];
assign temp=b[0:4]^a[5:9];
if(temp[0]!=1&&temp[1]!=1&&temp[2]!=1&&temp[3]!=1&&temp[4]!=1)
begin
out0<=0;
end
else if(temp[0]!=0&&temp[1]!=0&&temp[2]!=0&&temp[3]!=0&&temp[4]!=0)
begin
out0<=10;
b[0:4]<=!a[0:4];
end
else
begin
out0<=11;
b[0:4]<=temp[0:4];
end

assign temp1=a[0:4]^a[10:14];
if(temp1[0]!=1&&temp1[1]!=1&&temp1[2]!=1&&temp1[3]!=1&&temp1[4]!=1)
begin
out1<=0;
end
else if(temp1[0]!=0&&temp1[1]!=0&&temp1[2]!=0&&temp1[3]!=0&&temp1[4]!=0)
begin
out1<=10;
b[0:4]<=!b[0:4];
end
else
begin
out1<=11
b[0:4]<=temp1[0:4];
end

assign temp2=a[0:4]^a[15:19];
if(temp2[0]!=1&&temp2[1]!=1&&temp2[2]!=1&&temp2[3]!=1&&temp2[4]!=1)
begin
out2<=0;
end
else if(temp2[0]!=0&&temp2[1]!=0&&temp2[2]!=0&&temp2[3]!=0&&temp2[4]!=0)
begin
out2<=10;
b[0:4]<=!b[0:4];
end
else
begin
out2<=11
b[0:4]<=temp2[0:4];
end

end
endmodule

I dont know to assign value to b..,Help me to overcome the error....

Well you need to do a togle operation. So something like a tff is
To be considered and you probebly want to have a clock as well.
If you want to Read back your signal
You got to add it in sensitivity list as well.