Untitled

module full_adder(in0, in1, cin, out, cout);
	input in0, in1, cin;
	output out, cout;
    wire wire1, wire2, wire3; 

	xor xor1(wire1, in0, in1);
    and and1(wire2, wire1, cin);
    and and2(wire3, in0, in1);
    xor xor2(out, wire1, cin);
    or  or1(cout, wire2, wire3);

endmodule

module ripple_carry_adder (in0, in1, out, cout,s_overflow,u_overflow);
    // declare input signals
    input [3:0] in0;
    input [3:0] in1;

    // declare output signals
    output [3:0] out;
    output cout;
    output s_overflow;
    output u_overflow;

    // here is your design
    wire [3:0] in0, in1;
    wire c1, c2, c3;
    wire [3:0] out;
    wire cout, s_overflow, u_overflow;

    full_adder f0(in0[0], in1[0], 0, out[0], c1);
	full_adder f1(in0[1], in1[1], c1, out[1], c2);
	full_adder f2(in0[2], in1[2], c2, out[2], c3);
	full_adder f3(in0[3], in1[3], c3, out[3], cout);

    xor xor1(s_overflow, cout, c3);
    or  or1(u_overflow, cout);


endmodule