64. Full Adder

How do you plan to solve it?

// Half Adder primitive
module half_adder (
    input  a, b,
    output sum, carry
);
    // Write code here
    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
);
    // Write code here
    wire [1:0] layer1;
    wire carry_2;
    half_adder layerf (.a(a), .b(b), .sum (layer1 [0]), .carry(layer1 [1]));
    half_adder layer2 (.a(layer1[0]), .b(cin), .sum(sum), .carry(carry_2));
    assign cout = carry_2 | layer1 [1];
endmodule