答：以下是用Python编写的程序找出100以内的最大素数的代码：

This program finds the largest prime number under 100

n = 100 # Set the upper limit
prime_numbers = [] # Create an empty list to store prime numbers
for num in range(2, n + 1): # Iterate through numbers from 2 to n

is_prime = True # Assume number is prime until shown it is not  

for i in range(2, num): # Check for factors other than 1 and the number itself 

    if (num % i == 0): 
        is_prime = False  

if is_prime:  
    prime_numbers.append(num) # Add the number to list of primes 

print("The largest prime number under", n, "is", max(prime_numbers))