"C Language Programming (fourth Edition)" Reading Experience (ii)

Sixth. Referencing an array to process bulk data

1. Definition of array: type-character array-name [constant-expression]

1) define an array in the main function, the constant expression cannot contain the variable

int a[3+5];   // Legal int N; int a[n];       // Not legal

2) in the function being called, the length can be a variable or a very expressive expression

void int N) {     int a[2// Legal, because the value of n is constant when executing a function }

3) in the C language, the array name represents the starting address of the array, and if the input entry in the SCANF function is an array of characters, do not add the address character &

2. Initialization of arrays

If you specify an array's length and initialize it when you define a numeric array, the system automatically initializes the array elements that are not initialized by the initialization list.

is 0 (if it is a character array, it is initialized to ' \ s ', and if it is a pointer-type array, it is initialized to null (null pointer) )

int a[1,2,3,4,5};  // only the first five elements are initialized, and the last five elements are 0

3. Initialization of two-dimensional arrays

int a[3[4] = {{1},{5},{9/*  Post-assignment element   1  0  0  0   5  0  0  0   9  0  0  0 */

int a[3[4// define an array of three rows four columns a[3] [43//  Illegal, array starting from 0, does not exist a[3][4]

"C Language Programming (fourth Edition)" Reading Experience (ii)