Long strings

Question

Hey! I have seen c# code that uses the @ to tell the compiler the string has newlines in it and that it should be all in one line. Is there something like that for c/c++?

Like if I want to put something like:

73167176531330624919225119674426574742355349194934 96983520312774506326239578318016984801869478851843 85861560789112949495459501737958331952853208805511 12540698747158523863050715693290963295227443043557 66896648950445244523161731856403098711121722383113 62229893423380308135336276614282806444486645238749 30358907296290491560440772390713810515859307960866 70172427121883998797908792274921901699720888093776 65727333001053367881220235421809751254540594752243 52584907711670556013604839586446706324415722155397 53697817977846174064955149290862569321978468622482 83972241375657056057490261407972968652414535100474 82166370484403199890008895243450658541227588666881 16427171479924442928230863465674813919123162824586 17866458359124566529476545682848912883142607690042 24219022671055626321111109370544217506941658960408 07198403850962455444362981230987879927244284909188 84580156166097919133875499200524063689912560717606 05886116467109405077541002256983155200055935729725 71636269561882670428252483600823257530420752963450

In a string I don't want to place it all in one line but just put it like that and have the compiler know that that is only one line.

Answer 1

No, C and C++ don't have anything like C# verbatim string literals. The closest you can do is:

"73167176531330624919225119674426574742355349194934"
"96983520312774506326239578318016984801869478851843" 
"85861560789112949495459501737958331952853208805511"  
"12540698747158523863050715693290963295227443043557" 
"66896648950445244523161731856403098711121722383113" 
"62229893423380308135336276614282806444486645238749" 
"30358907296290491560440772390713810515859307960866" 
"70172427121883998797908792274921901699720888093776" 
"65727333001053367881220235421809751254540594752243"  
"52584907711670556013604839586446706324415722155397" 
"53697817977846174064955149290862569321978468622482" 
"83972241375657056057490261407972968652414535100474" 
"82166370484403199890008895243450658541227588666881" 
"16427171479924442928230863465674813919123162824586"  
"17866458359124566529476545682848912883142607690042"
"24219022671055626321111109370544217506941658960408" 
"07198403850962455444362981230987879927244284909188" 
"84580156166097919133875499200524063689912560717606" 
"05886116467109405077541002256983155200055935729725"     
"71636269561882670428252483600823257530420752963450"

Note however that even in C# it doesn't do what it sounds like you want. If you have:

string foo = @"x
y";

in C# then the string will actually contain a linebreak.

Answer 2

In C and C++ you can do this:

const char* str = "73167176531330624919225119674426574742355349194934"
                  "96983520312774506326239578318016984801869478851843";

and the compiler will automatically concatenate these into a single string.

Answer 3

C and C++ have automatic concatenation of adjacent quoted strings. This means that

const char *a = "a" "b";

and

const char *b = "ab";

will make a and b point at identical data. You can of course extend this, but it becomes troublesome when the strings contain quotes. Your example seems not to, so it might be practical then.

Answer 4

Sure, you can do:

char *x = "73167176531330624919225119674426574742355349194934\n"
          "96983520312774506326239578318016984801869478851843\n"
                     <lines removed for brevity>
          "71636269561882670428252483600823257530420752963450";

and this will emulate the @"" behavior exactly (including the line breaks).

If you really want it as one line with no line breaks, don't put the "\n" newline characters in, but that's slightly different to the way the @"" stuff works in C#.

Answer 5

Thanks for all the answers :D

Answer 6

Another alternative is to end a line with a \, upon seeing which the preprocessor will delete the following newline:

const char *str = "Hello,\
 World!";

It's not as pretty as relying on the automatic concatenation of adjacent string literals as said above; but should be mentioned anyway.