import tensorflow as tf

# Initialize count with value 0
count = tf.Variable(0)

newVal = tf.add(count,1)
# Assign operation updates the value of ref
# https://www.tensorflow.org/api_docs/python/tf/assign
assignment = tf.assign(count,newVal)

with tf.Session() as sess:
    sess.run(tf.global_variables_initializer())
    
    # Now update the count 5 times
    for count in range(5):
        print(sess.run(assignment))