Character Arrays - char[]

In C/C++, arrays are a contiguous block of memory used to store multiples of a particular data type. By storing an array of characters, we are storing an array of 8-bit integers that map to characters in the ASCII table.

The following code creates two c-strings (char arrays). The first is not initialised, and has space for twenty characters. The second is initialised and has the space to store “hello”.

#include <stdio.h>

int main()
{
  char name[20];
  char other[] = "Hello";

  printf("Enter your name: ");
  scanf("%s", name);

  printf("%s %s\n", other, name);
}

When you run this, it will output a hello message that includes the user’s name. For example:

Enter your name: Andrew
Hello Andrew

How does the printf function know the number of characters in the user’s name? The array had twenty characters, and yet it only printed the six characters from the name.

Let’s have a look at how this works.