This function is used for defining the structure which is required.

This function is used to define a structure object of the type, which is created by the defstruct operation.

This function is used to specifically assign values to key values by explicitly defining which values get assigned to which keys in the structure.

Individual fields of the structure can be accessed by accessing the keys along with the structure object.

By default structures are also immutable, so if we try to change the value of a particular key, it will not change.

Since structures are immutable, the only way that another key can be added to the structure is via the creation of a new structure. An example on how this can be achieved is shown in the following program.