PYTHON

Finding the sum of even Fibonacci numbers less than or equal to given limit

# Find the sum of all the even-valued  
# terms in the Fibonacci sequence which  
# do not exceed given limit. 
  
# Returns sum of even Fibonacci numbers which 
# are less than or equal to given limit. 
def evenFibSum(limit) : 
    if (limit < 2) : 
        return 0
  
    # Initialize first two even prime numbers 
    # and their sum 
    ef1 = 0
    ef2 = 2
    sm= ef1 + ef2 
      
    # calculating sum of even Fibonacci value 
    while (ef2 <= limit) : 
  
        # get next even value of Fibonacci  
        # sequence 
        ef3 = 4 * ef2 + ef1 
  
        # If we go beyond limit, we break loop 
        if (ef3 > limit) : 
            break
  
        # Move to next even number and update 
        # sum 
        ef1 = ef2 
        ef2 = ef3 
        sm = sm + ef2 
      
    return sm 
  
# Driver code 
limit = 400
print(evenFibSum(limit)) 
  
# This code is contributed by Nikita Tiwari.