Trigraph is a sequence of three characters. The first two always are question marks "??".
Trigraphs are equivalent to some single characters. Here is a table from trigraphs and their equivalents
|
Trigraph |
Equivalent |
|
??! |
| |
|
??< |
{ |
|
??> |
} |
|
??/ |
\ |
|
??' |
^ |
|
??- |
~ |
|
??= |
# |
|
??( |
[ |
|
??) |
] |
This can cause some problems for new programmers. See this example
// This will be executed???????????/ i++;
This line of code will not be executed, because is used a trigraph "??/" the compiler will not compile the line.
Digraphs are used for the same issues as the trigraphs, see the digraphs
|
Digraph |
Equivalent |
|
<: |
[ |
|
:> |
] |
|
<% |
{ |
|
%> |
} |
|
%: |
# |
|
%:%: |
## |



