// Half Adder primitive
module half_adder (
input a, b,
output sum, carry
);
assign sum = a ^ b ;
assign carry = a & b ;
endmodule
// Full Adder using 2 Half Adders
module full_adder_struct (
input a, b, cin,
output sum, cout
);
wire sumw1 , carryw1 , carryw2;
half_adder ins1(a,b,sumw1,carryw1);
half_adder ins2(sumw1,cin,sum,carryw2);
assign cout = carryw1 | carryw2 ;
endmodule