/*
:name: casex
:description: A module testing casex statement
:should_fail: 0
:tags: 12.5.1
*/
module case_tb ();
	wire [3:0] a = 4'b10zx;
	reg [3:0] b = 0;
	always begin
		casex(a)
			4'b1xz?: b = 1;
			4'b01xx: b = 2;
			4'b001x: b = 3;
			4'b0001: b = 4;
			default b = 0;
		endcase
	end
endmodule