If I understand what you want to do correctly, you should be able to use the increment package in vim. Take your first line of text and paste it 15 times using 15p
:
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
Bit(in=in[0], load=load, out=out[0]);
You can select the '0' on the first line, and enter visual block mode using Ctrl-V. Highlight to the bottom while in visual block mode, so that all of the 0s are highlighted. Then you can type :Inc<CR>
. This will increment the numbers, essentially numbering your lines in text:
Bit(in=in[ 0], load=load, out=out[0]);
Bit(in=in[ 1], load=load, out=out[0]);
Bit(in=in[ 2], load=load, out=out[0]);
Bit(in=in[ 3], load=load, out=out[0]);
Bit(in=in[ 4], load=load, out=out[0]);
Bit(in=in[ 5], load=load, out=out[0]);
Bit(in=in[ 6], load=load, out=out[0]);
Bit(in=in[ 7], load=load, out=out[0]);
Bit(in=in[ 8], load=load, out=out[0]);
Bit(in=in[ 9], load=load, out=out[0]);
Bit(in=in[10], load=load, out=out[0]);
Bit(in=in[11], load=load, out=out[0]);
Bit(in=in[12], load=load, out=out[0]);
Bit(in=in[13], load=load, out=out[0]);
Bit(in=in[14], load=load, out=out[0]);
Bit(in=in[15], load=load, out=out[0]);