Ripple Carry Adder and quartus

module full_adder(S, Cout, A, B, Cin);

  output S;

  output Cout;

  input A;

  input B;

  input Cin;

  wire nor1_out, and1_out, and2_out;

  nor nor1(nor1_out,A,B);

  nor nor2(S, nor1_out, Cin);

  and and1(and1_out, Cin, nor1_out);

  and and2(and2_out, A, B);

  or or1(Cout, and1_out, and2_out);

endmodule

module ripple_carry_adder

(

  output Cout, 

  output [7:0]Sum, 

  output overflow_flag, 

  input [7:0]A, 

  input [7:0]B, 

  input Cin

);

reg mytemp, mytemp2;

full_adder A1(Sum[0], mytemp, A[0], B[0], Cin);

full_adder A2(Sum[1], mytemp2, A[1], B[1], mytemp);

full_adder A3(Sum[2], mytemp, A[2], B[2], mytemp2);

full_adder A4(Sum[3], mytemp2, A[3], B[3], mytemp);

full_adder A5(Sum[4], mytemp, A[4], B[4], mytemp2);

full_adder A6(Sum[5], mytemp2, A[5], B[5], mytemp);

full_adder A7(Sum[6], mytemp, A[6], B[6], mytemp2);

full_adder A8(Sum[7], Cout, A[7], B[7], mytemp);

//if(Cout==1) overflow_flag=1;

//else overflow_flag=0;

endmodule