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

module add7 (cout2,cout1,s,a,b,c,d,e,f,g);
input a,b,c,d,e,f,g;
output cout2,cout1,s;
add6 ad1 (c2,c1,s1,a,b,c,d,e,f);
ha h1 (c3,s,s1,g);
ha h2 (c4,cout1,c3,c1);
ha h3 (c5,cout2,c4,c2);
endmodule

 Testbench :-

module adtb ();

reg a,b,c,d,e,f,g;

wire cout2,cout1,s;

add7 dut (cout2,cout1,s,a,b,c,d,e,f,g);

integer j;

initial

begin

for (j=0;j<=127;j=j+1)

begin

{a,b,c,d,e,f,g}= j;

#1;

$display(a,b,c,d,e,f,g,":",cout2,cout1,s);

end

end

endmodule