What is significance of an asterisk (*) ?

The symbol asterisk (*) tells the computer that you are declaring a pointer.

Actually it depends on context.
– In a statement like int *ptr; the ‘*’ tells that you are declaring a pointer.
– In a statement like int i = *ptr; it tells that you want to assign value pointed to by ptr to variable i.
– The symbol “*” is also called as Indirection Operator/ Dereferencing Operator.

In General,
An asterisk (*); from Late Latin asteriscus, from Ancient Greek ἀστερίσκος, asteriskos, “little star”) is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star.

Computer scientists and mathematicians often vocalize it as star (as, for example, in the A* search algorithm or C*-algebra). In English, an asterisk is usually five-pointed in sans-serif typefaces, six-pointed in serif typefaces,[citation needed] and six- or eight-pointed when handwritten.

It is often used to censor offensive words, and on the Internet, to indicate a correction to a previous message.