写出两位全加器的testbench代码

很高兴为您解答问题。以下是两位全加器的testbench代码：

`module full_adder_tb;

reg [1:0] a, b, cin;
wire [1:0] sum;
wire cout;

full_adder fa(
.a(a),
.b(b),
.cin(cin),
.sum(sum),
.cout(cout)
);

initial
begin
a = 0; b = 0; cin = 0;
#10 a = 0; b = 1; cin = 0;
#10 a = 1; b = 0; cin = 0;
#10 a = 1; b = 1; cin = 0;
#10 a = 0; b = 0; cin = 1;
#10 a = 0; b = 1; cin = 1;
#10 a = 1; b = 0; cin = 1;
#10 a = 1; b = 1; cin = 1;
end

endmodule`

希望能为您提供帮助！