module full_adder (a1, a2, c_in, s, c_out); 
input  a1, a2, c_in;
output s, c_out;    

assign s = a1 ^ a2 ^ c_in;             
assign c_out = (a1 & a2) | (a1 & c_in) | (a2 & c_in);  

endmodule