说明：  three udf function This is a real single point crossover function for genetic algorithm based projects under vb.net or excel vba usage a1=crosover(a1, b1, m, 1) b1 = crosover(a1, b1, m, 2) crossover with a1 and b1 are strings, m is a random number between len(a1) or len(b1) b1 = crosover(a1, b1, m, 2) crossover b1 and a1 are strings, m is a random number between len(a1) or len(b1) The second is a mutation function The third function converts decimal to binary with the given digit. example decimal(2)=binary(10) normal eveybody can write so function my function will show the binary with n digit if n=20 DECTOBINDI(2, 20)=00000000000000000010 It can be used to write genetic algorithm based functions Finally normal function decto bin to understand differencases.