function output_symbol=graycoding(input_symbol)

len=length(input_symbol);
for i=1:len
    if (input_symbol(i)==0),
        output_symbol(i)=0;
    elseif(input_symbol(i)==1),
        output_symbol(i)=1;
    elseif(input_symbol(i)==2),
        output_symbol(i)=3;
    elseif(input_symbol(i)==3),
        output_symbol(i)=2;
    elseif(input_symbol(i)==4),
        output_symbol(i)=7;
    elseif(input_symbol(i)==5),
        output_symbol(i)=6;
    elseif(input_symbol(i)==6),
        output_symbol(i)=4;
    else
        output_symbol(i)=5;
    end
end