Why allow concatenation of string literals?

Question

I was recently bitten by a subtle bug.

char ** int2str = {
   \"zero\", // 0
   \"one\",  // 1
   \"two\"   // 2
   \"three\",// 3
   nullptr };

assert( int         


        

Answer 1

From the python lexical analysis reference, section 2.4.2:

This feature can be used to reduce the number of backslashes needed, to split long strings conveniently across long lines, or even to add comments to parts of strings

http://docs.python.org/reference/lexical_analysis.html

Answer 2

Sure, it's the easy way to make your code look good:

char *someGlobalString = "very long "
                         "so broken "
                         "onto multiple "
                         "lines";

The best reason, though, is for weird printf formats, like type forcing:

uint64_t num = 5;
printf("Here is a number:  %"PRIX64", what do you think of that?", num);

There are a bunch of those defined, and they can come in handy if you have type size requirements. Check them all out at this link. A few examples:

PRIo8 PRIoLEAST16 PRIoFAST32 PRIoMAX PRIoPTR

Answer 3

I certainly have in both C and C++. Offhand, I don't see much relationship between its utility and how "modern" the language is.

Answer 4

I'm not sure about other programming languages, but for example C# doesn't allow you to do this (and I think this is a good thing). As far as I can tell, most of the examples that show why this is useful in C++ would still work if you could use some special operator for string concatenation:

string someGlobalString = "very long " +
                          "so broken " +
                          "onto multiple " +
                          "lines"; 

This may not be as comfortable, but it is certainly safer. In your motivating example, the code would be invalid unless you added either , to separate elements or + to concatenate strings...