In C, you only need to free() a string (which is a char array) if its memory was dynamically allocated using a function like malloc(), calloc(), or realloc().
You allocate memory so you should free it. a="abc"; This assigns a pointer to a constant string to your char* a , by doing so you loose the pointer to the memory allocated in the first line, you should never free constant strings. Use strcpy(a,"abc"); instead of a="abc"; to move the string into your allocated memory.
You need to call free for any pointer that has been dynamically allocated. There are three calls that do dynamic allocation: malloc. calloc.
The strcpy function itself doesn't allocate memory for the destination string so, no, it doesn't have to be freed.
Note that including the <string> header is essential for working with C++ string functions, allowing us to manipulate strings efficiently.
I dove into the latest reports, safety guidance, and C++26 updates so you don't have to. According to the January TIOBE Index, C++ is currently the fourth most popular programming language after C and Python. C++ is the main programming language used in many critical systems, including hospitals, cars, and airplanes.
The C++ programming language has support for string handling, mostly implemented in its standard library. The language standard specifies several string types, some inherited from C, some designed to make use of the language's features, such as classes and RAII.
Going faster than memcpy
Memcpy is just a memory copy, it does nothing smart under the hood - nor it should. memcpy is meant to be the fastest library routine for memory-to-memory copy. As such, you need to free all objects, dogs, cats, sqirrels etc.
*p++ uses postincrement ( ++ ; see Postincrement and Postdecrement) on the pointer p . That expression parses as *(p++) , because a postfix operator always takes precedence over a prefix operator. Therefore, it dereferences the entering value of p , then increments p afterwards.
Explanation. The error occurs because the C language does not allow adding two pointer types. Pointers can only be added to integers (which indicate the offset of the pointer), not other pointers.
In general - any memory allocated dynamically - using calloc/malloc/realloc needs to be freed using free() before the pointer goes out of scope. If you allocate memory using 'new' then you need to free it using 'delete'.
For printf, %d and %i are synonyms. They're functionally identical. In scanf, %d only matches decimal, whereas %i can match to decimal, octal, and hexadecimal.
Using printf() we can print any character, symbol or number, but it seems a bit difficult to print % using printf(). If we simply write “%” in printf(), it will not print % and will show an error. For printing '%', there is a specific format specifier i.e; “%%”, using this in printf() we can print %.
Unlike many other programming languages, C does not have a String type to easily create string variables. Instead, you must use the char type and create an array of characters to make a string in C: char greetings[] = "Hello World!"; Note that you have to use double quotes ( "" ).
If your profiling shows memcpy is the bottleneck, 99% of the time that's going to mean the bottleneck is simply the fact that you're making copies, to optimize further you'd have to restructure things to make less.
But the free() method is not compulsory to use. If free() is not used in a program the memory allocated using malloc() will be de-allocated after completion of the execution of the program (included program execution time is relatively small and the program ends normally).
While researching the upcoming — and significant — C23 version of the C programming language, I learned something surprising: The memset() function will be deprecated. It effectively does nothing when used in the C23 standard. The reason makes a lot of sense. I wrote about the memset() function in a Lesson from 2021.
NASA employs a diverse array of programming languages, including C, C++, Python, Fortran, MATLAB, and Java. This variety underscores the agency's commitment to precision and innovation in space exploration.
Some people habitually use memcpy(), maybe because they learned C before the C99 standard was implemented and C gained the capability of structure assignment. However, *b = *a above is better, because it's type-safe, while memcpy() discards type information and thus is more prone to programmer mistakes.
The message is clear and direct, just like your feelings.
When we have strings in our code, we need to keep in mind that in C programming language this is not a native data type; instead, we are working with arrays of characters.
There are actually two types of strings in C++ . The C++ string or just string from the <string> library is the more modern type, and it is very similar to the Python string class. The old style C-string which is essentially an array of char type. The char type itself is actually distinct from both types of strings.
Wide string literals
A wide string literal is a null-terminated array of constant wchar_t that is prefixed by ' L ' and contains any graphic character except the double quotation mark ( " ), backslash ( \ ), or newline character.