64. Full Adder

// 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 S1, C1, S2, C2;

    half_adder ha_inst1 (a, b, S1, C1);
    half_adder ha_inst2 (S1, cin, S2, C2);

    assign sum = S2;
    assign cout = C2 | C1;

endmodule