64. Full Adder

How do you plan to solve it?

// 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 a_plus_b;
    wire carry1;
    wire carry2;

    half_adder ha1(.a(a), .b(b), .sum(a_plus_b), .carry(carry1));
    half_adder ha2(.a(a_plus_b), .b(cin), .sum(sum), .carry(carry2));
    assign cout = carry1 | carry2;
endmodule