# Forward Iterator

### Description

A Forward Iterator is an Input Iterator that guarantees a linear traversal over the sequence.

### Refinement of

Input Iterator

### Valid expressions

Forward Iterator does not define any new expressions beyond those defined in Input Iterator. However, some of the restrictions described in Input Iterator are relaxed.

Expression | Expression type
--- | ---
`typename i::next` | A model of Forward Iterator

### Invariants

For any forward iterators i and j the following invariants always hold:

- if `i` and `j` are dereferenceable and `i` is identical to `j`, then `i::next` is identical to `j::next`.

### See also

Forward Sequence, Input Iterator, Bidirectional Iterator

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Last edited July 15, 2002 10:53 am