Take into account that you may not use pointer to declared like. Does "nonmodifiable" in C mean the same as "immutable" in other programming languages? At this point string pointed to by start contains all characters of the source except null character ('\0'). It uses malloc to do the actual allocation so you will need to call free when you're done with the string. i have some trouble with a simple copy function: It takes two pointers to strings as parameters, it looks ok but when i try it i have this error: Working with C Structs Containing Pointers, Lesson 9.6 : Introducing the char* pointer, C/C++ : Passing a Function as Argument to another Function | Pointers to function, Copy a string into another using pointer in c programming | by Sanjay Gupta, Hi i took the code for string_copy from "The c programing language" by Brian ecc. I think the confusion is because I earlier put it as. The numerical string can be turned into an integer with atoi if thats what you need. \$\begingroup\$ @CO'B, declare, not define The stdlib.h on my system has a bunch of typedefs, #defines, and function declarations like extern double atof (const char *__nptr); (with some macros sprinkled in, most likely related to compiler-specific notes) \$\endgroup\$ - I replaced new char(varLength) with new char(10) to see if it was the size that was being set, but the problem persisted. An Example Of Why An Implicit Cast From 'char**' To 'const char**' Is Illegal: void func() { const TYPE c; // Define 'c' to be a constant of type 'TYPE'. I tend to stay away from sscanf() or sprintf() as they bring in 1.7kB of additional code. std::basic_string<CharT,Traits,Allocator>:: copy. That is the only way you can pass a nonconstant copy to your program. As has been shown above, several such solutions exist. Even though all four functions were used in the implementation of UNIX, some extensively, none of their calls made use of their return value. Copy constructor takes a reference to an object of the same class as an argument. But this will probably be optimized away anyway. ], will not make you happy with the strcpy, since you actually need some memory for a copy of your string :). Because the charter of the C standard is codifying existing practice, it is incumbent on the standardization committee to investigate whether such a function already exists in popular implementations and, if so, consider adopting it. char * ptrFirstHash = strchr (bluetoothString, #); const size_t maxBuffLength = 15; char const* implies that the class does not own the memory associated with it. We need to define our own copy constructor only if an object has pointers or any runtime allocation of the resource like a file handle, a network connection, etc. If we remove the copy constructor from the above program, we dont get the expected output. Getting a "char" while expecting "const char". To perform the concatenation, one pass over s1 and one pass over s2 is all that is necessary in addition to the corresponding pass over d that happens at the same time, but the call above makes two passes over s1.