CODEWITHSUNDEEP
c
Richard
Richard

Reputation: 69

Unknown escape sequence

I am trying to printf a string that shows a temperature table printf("TABLE 24A (20\°C)");

The degree sign is a constant I have defined as 0xDF so the the string looks like this: "TABLE 24A (20\xDF C)"

This works but looks incorrect because of the space between the \xDF and the C. If I remove the space the compiler issues a warning hex escape sequence out of range.

If I modify the string to "TABLE 24A (20\xDF\C)" I get the correct result but the compiler issues warning unknown escape sequence: '\C'

Is there a way to get rid of the warnings but lose the space between the two characters?

Upvotes: 3

Views: 2518

Answers (2)

John Kugelman
John Kugelman

Reputation: 362127

\x escape sequences consume as many adjacent hex digits as possible. The C is being parsed as a hex digit.

With \x, you could combine two adjacent string literals.

printf("**TABLE 24A (20\xDF""C)**");

Or use a \unnnn Unicode escape, which is limited to four hex characters.

printf("**TABLE 24A (20\u00DFC)**");

Or octal \nnn:

printf("**TABLE 24A (20\337C)**");

Upvotes: 8

dbush
dbush

Reputation: 225507

You can take advantage of the fact that consecutive string literals are automatically concatenated:

 printf("**TABLE 24A (20\xDF" "C)**");

This prevents the parser from consuming more characters for the escape sequence than you want.

You could also pass in the character as a parameter and use the %c format specifier to print it:

printf("**TABLE 24A (20%cC)**", '\xDF');

Upvotes: 9

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