题解 | #五到一选择器#

`timescale 1ns/1ns

module top_module( 
    input [3:0] a, b, c, d, e, 
    input [2:0] sel,
    output reg [3:0] out );
    //此题考察case 选择语句
    always@(*)begin
        case(sel)
            0: out = a;
            1: out = b;
            2: out = c;
            3: out = d;
            4: out = e;
            default: out = 'd0;
        endcase
    end
endmodule