structure definitions consisting of a list of declarations enclosed in braces, that is curly brackets or {}

function definitions containing a list of parameter declarations enclosed in parentheses, that is round brackets or ()

array declarations enclosed in square brackets or []

characters enclosed by double quotes, for example printf(“\n”);

character constants enclosed by single quotes, for example if (c == ‘\n’)

comments

conditions specified by if/else

conditions evaluated during preprocessing specified by #if/#else/#endif.

Searching pairs

Matching pairs

Matching nested pairs

Enclosing.