65. Ripple Carry Adder

How do you plan to solve it?

// 1-bit Full Adder (to be used by the 4-bit RCA)
module full_adder_1bit (
    input  a, b, cin,
    output sum, cout
);
    assign {cout,sum}=a+b+cin;
    // TODO: implement 1-bit full adder (structural or dataflow)

endmodule

// 4-bit Ripple Carry Adder – chain 4 full adders
module rca4_chain (
    input  [3:0] a,
    input  [3:0] b,
    input        cin,
    output [3:0] sum,
    output       cout
);
    // TODO: Declare internal ripple carries
    wire [4:0]c;
    // TODO: instantiate 4 full adders and chain carries
    assign c[0]=cin;
    genvar z;
    generate
    for(z=0;z<4;z=z+1) 
        full_adder_1bit f(a[z],b[z],c[z],sum[z],c[z+1]);
    endgenerate
    // TODO: drive cout
    assign cout=c[4];


endmodule