do we need to use epochs in all neural network code example

Example 1: epoch neural network definition

One Epoch is when an ENTIRE dataset is passed forward and backward 
through the neural network only ONCE.

Example 2: Epoch vs Batch Size vs Iterations

One Epoch is when an ENTIRE dataset is passed forward and backward 
through the neural network only ONCE.

Batch Size is the Total number of training examples present in a 
single batch.

Iterations is the number of batches needed to complete one epoch.