This is an extension of recommendation: STR30-C. Do not attempt to modify string literals

Since string literals are constant, they should only be assigned to constant pointers as indicated below:

char* c1 = "Hello"; // Bad: assigned to non-const
char c2[] = "Hello"; // Bad: assigned to non-const
char c3[6] = "Hello"; // Bad: assigned to non-const
c1[3] = 'a'; // Undefined (but compiles)
const char* c1 = "Hello"; // Good
const char c2[] = "Hello"; // Good
const char c3\[6] = "Hello"; // Good
c1[3] = 'a'; // Compile error

By assigning string literals to constant pointers the compiler will warn you if you try to modify them. 

References:

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/1993/N0389.asc;

[Lockheed Martin 2005] Lockheed Martin. Joint Strike Fighter Air Vehicle C++ Coding Standards for the System Development and Demonstration Program. Document Number 2RDU00001, Rev C. December 2005.     AV Rule 151.1