gates and vectors

You are given a four-bit input vector in[3:0]. We want to know some relationships between each bit and its neighbour:

out_both: Each bit of this output vector should indicate whether both the corresponding input bit and its neighbour to the left (higher index) are '1'. For example, out_both[2] should indicate if in[2] and in[3] are both 1. Since in[3] has no neighbour to the left, the answer is obvious so we don't need to know out_both[3].
out_any: Each bit of this output vector should indicate whether any of the corresponding input bit and its neighbour to the right are '1'. For example, out_any[2] should indicate if either in[2] or in[1] are 1. Since in[0] has no neighbour to the right, the answer is obvious so we don't need to know out_any[0].
out_different: Each bit of this output vector should indicate whether the corresponding input bit is different from its neighbour to the left. For example, out_different[2] should indicate if in[2] is different from in[3]. For this part, treat the vector as wrapping around, so in[3]'s neighbour to the left is in[0].

Gatesv - HDLBits (01xz.net)

module top_module( 
    input [3:0] in,
    output [2:0] out_both,
    output [3:1] out_any,
    output [3:0] out_different );
integer i;
    
    always @(*) begin
        for(i=0;i<3;i++) begin
            out_both[i] = in[i] & in[i+1];
            out_any[i+1] = in[i+1] | in[i];
            out_different[i] = in[i] ^ in[i+1];
        end
        out_different[3] = in[0] ^ in[3];   // 因为这一点在循环中并不能实现掉头，要另外写一个
    end

endmodule