10 i/p (1bit wide) ADDER:-

module add10 (cout3,cout2,cout1,s,a,b,c,d,e,f,g,h,i,j);
input a,b,c,d,e,f,g,h,i,j;
output cout3,cout2,cout1,s;
add9 ad1 (c3,c2,c1,s1,a,b,c,d,e,f,g,h,i);
ha h1 (c4,s,s1,j);
ha h2 (c5,cout1,c4,c1);
ha h3 (c6,cout2,c5,c2);
ha h4 (c7,cout3,c6,c3);
endmodule

 TEST BENCH:-

module adtb ();
reg a,b,c,d,e,f,g,h,i,j;
wire cout3,cout2,cout1,s;
add10 dut (cout3,cout2,cout1,s,a,b,c,d,e,f,g,h,i,j);
integer z;
initial
begin
for (z=0;z<=1023;z=z+1)
begin
{a,b,c,d,e,f,g,h,i,j}= z;
#1;
$display(a,b,c,d,e,f,g,h,i,j,":",cout3,cout2,cout1,s);
end
end
endmodule