Initialization vs. Destination in C

Question

Recently, my teacher said that array initialization in C occurs in two ways:

• In the manual style int a[5]={1,2,3,4,5};
• Use scanf()asint a[5], i; for(i=0;i<5;i++) scanf("%d", &a[i]);

In my opinion, the second "path" is the assignment method, not the initialization. So I decided to check what people here can say about it. I came across this one where one answer states:

If all you ask is terminology (*, which is not entirely clear from your question), the "Initialization" of a variable is, literally, the first time it is assigned a value. This term comes from the fact that you give the variable this "initial" value.

This should (obviously) happen before it is used for the first time.

int x=5; is an announcement and initialization, and it's really just a convenient shortened version for

int x; x=5;

If I follow what this particular answer states, then the second way to “initialize” is correct, because no value scanf()has been assigned before the expression . However, thanks to my knowledge of static variables, a new doubt arises in my mind. Consider the following code:

#include <stdio.h>

void first_way(){
    static int x[2]={1,2};
    printf("first_way called %d time(s)\n",++x[0]);
}

void second_way(){
    int i;
    static int x[2];
    for(i=0;i<2;i++)scanf("%d",&x[i]);
    printf("second_way called %d time(s)\n",++x[0]);
}

int main(void){
    int i;
    for(i=0;i<3;i++)
        first_way();
    printf("\n#######\n");
    for(i=0;i<3;i++)
        second_way();
    return 0;
}

His output looks like this:

first_way called 2 time(s)
first_way called 3 time(s)
first_way called 4 time(s)

#######
1 2
second_way called 2 time(s)
1 2
second_way called 2 time(s)
1 2
second_way called 2 time(s)

This conclusion again makes me think of the version scanf()as an assignment version rather than initializing it, even if scanf()no value was assigned to the elements before the expression x[]. Return to the square.

So, the second version is really initialization, for example, my instructor or just an appointment (what I think)?

Edit:

, - , , static , static 0 , . - const.

const int x = 2; x, . , ( ):

int x = 5; - , int x; x=5;

, , scanf() ?

Answer 1

C (1).

. .

, , . - " ". C ? , , , " ".

( C), "" "" ( C, C) ..

, { int b; b = 5; } ( C Standard , ), , , , b .

Answer 2

1)

 int a;

2)

int a=10;

3) Assignmen

a=10;

, .

int arrA[3] = {1,3,2};

:

arrB = arrA; 

Answer 3

N1570 6.7.9.1:

  initializer:
           assignment-expression
           { initializer-list }
           { initializer-list , }
  initializer-list:
           designationopt initializer
           initializer-list , designationopt initializer
  designation:
         designator-list =
  designator-list:
         designator
         designator-list designator
  designator:
         [ constant-expression ]
         . identifier

, , "". . , , , 10000 .

Answer 4

.

- .

int n = 42;

42 .

n = 42;

42 initializer; n = 42 .

, "initialized", , . , N1570 6.3.2.1:

lvalue , register ( ), ( ), undefined.

, , , - , , , , .

Answer 5

, . "" , .

, " ", " ". "static int x [2] = {1,2}", , "1, 2", X, , . , x [0] .

"static int x [2]", x, , . , - , x [0]. , , , x .

.