C char array initialization

This is not how you initialize an array, but for:

  1. The first declaration:

    char buf[10] = "";
    

    is equivalent to

    char buf[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    
  2. The second declaration:

    char buf[10] = " ";
    

    is equivalent to

    char buf[10] = {' ', 0, 0, 0, 0, 0, 0, 0, 0, 0};
    
  3. The third declaration:

    char buf[10] = "a";
    

    is equivalent to

    char buf[10] = {'a', 0, 0, 0, 0, 0, 0, 0, 0, 0};
    

As you can see, no random content: if there are fewer initializers, the remaining of the array is initialized with 0. This the case even if the array is declared inside a function.


  1. These are equivalent

    char buf[10] = "";
    char buf[10] = {0};
    char buf[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    
  2. These are equivalent

    char buf[10] = " ";
    char buf[10] = {' '};
    char buf[10] = {' ', 0, 0, 0, 0, 0, 0, 0, 0, 0};
    
  3. These are equivalent

    char buf[10] = "a";
    char buf[10] = {'a'};
    char buf[10] = {'a', 0, 0, 0, 0, 0, 0, 0, 0, 0};