Doubt with cstring and string

The library cstring(also accessible via string.h) is a library imported from C. Since C is not an object-oriented language, it is focused on working with arrays of type char*. Thus, we find functions such as:

• strcpy: Copy a text string
• strlen: Length of a text string
• strcat: Concatenates two text strings

The library stringis proprietary to C++. This library revolves around the class std::stringthat is the natural replacement for char*. The advantages of using this class over char*are several:

• You don't have to worry about dynamic memory management
• No need to manage your own buffers (eg: char buffer[500])
• Has no capacity limitations
• It supports char*via functionstring.c_str()

The class string, very simply, encapsulates a type pointer charand manages its life cycle. It allows you to write code faster, safer since, for example, it prevents it from being written outside the memory reserved for that purpose, and more readable.

An example of readability:

char* charFunc(const char* cadena1, int numero)
{
  size_t len = strlen(cadena1);
  len += log10(numero) + 1; // Número de dígitos del número
  len += 1; // Espacio para el caracter '\0'
  char* ptr = new char[](len);

  if( ptr )
    sprintf(ptr,"%s%d",cadena1,numero);

  return ptr;
}

std::string stringFunc(const std::string& cadena1, int numero)
{
  return cadena1 + std::to_string(numero);
} 

int main()
{
  // Versión char*
  char* cadena1 = charFunc("Una prueba",10);
  std::cout << cadena1 << '\n';
  delete[] cadena1;

  // Versión string
  std::string cadena2 = stringFunc("Una prueba",10);
  std::cout << cadena2 << '\n';
  // No necesita delete
}

The cstring header has functions to handle C-style strings, functions like strlen and strcpy

The string header provides the std::string class and related functions and operators.

The headers have similar names, but they're not really related beyond that. They cover separate tasks.