Initialization of arrays and two-dimensional arrays, pointers and arrays

1, the initialization of the array, relatively simple, the instance is as follows:

#include <stdio.h># define M 12int main (void) {int Days[m]={31,28,31,30,31,30,31,30,30,31,30,31};int i;for (i=0;i <m;i++) printf ("Months%d has%2d days.\n", I+1,days[i]); return 0;}

The results of the operation are as follows:

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M02/9D/C2/wKiom1mFclGASF3AAAAbKFdFV3Y993.png "title=" Untitled. png "alt=" Wkiom1mfclgasf3aaaabkfdfv3y993.png "/>

2. Uninitialized array:

Instance program;

#include <stdio.h># define M 12int main (void) {int n[m];//non-initialized array int days[m]={ 31,28,31,30,31,30,31,30,30,31,30,31};int i;for (i=0;i<m;i++)//printf ("Months%d has%2d days.\n", I+1,days[i]); printf ("%d%d\n", I,n[i]); return 0;}

Operation Result:

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M02/9D/C3/wKiom1mFdDri7apAAAAYrBIX32k377.png "title=" Untitled. png "alt=" Wkiom1mfddri7apaaaayrbix32k377.png "/>

It can be concluded that before initialization, the value of the array element is indeterminate, and the compiler uses a value that is already in the storage unit, and the output above is not necessarily.

3, in the initialization of the array, the compiler is very witty, even if you give the number of elements less than or for a given array size, the compiler will automatically recognize, not enough, it will use 0 instead. However, when there are too many pairs of numbers in the initialization list, the compiler warns of errors. Too many initializers too much initialization. The following is the deletion of several elements, the result:

#include <stdio.h># define M 12int main (void) {int n[m];//non-initialized array int days[m]={31,28,31,30,31,30,31,30};int i;for (i=0;i<m;i++) printf ("Months%d has%2d days.\n", I+1,days[i]);//printf ("%d%d\n", I,n[i]); return 0;}

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M02/9D/C3/wKiom1mFdXOjwzWwAAAu-P9F5DE654.png "title=" Untitled. png "alt=" Wkiom1mfdxojwzwwaaau-p9f5de654.png "/>

4, two-dimensional array, for a chestnut: float rain[5] [12] First,Rain[5] represents an array of five elements, for each element of the case, you need to see the rest of the declaration. The remaining is the float "12", which represents an array of 12 floating-point numbers. In summary, the two-dimensional array represents: Rain has 5 elements, and each element is an array of 12 numeric values.

The specific understanding of the drawing is as follows: It is quite clear.

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M00/9D/C4/wKioL1mFmnizRzCMAAQqD84Jjmo021.jpg "title=" Drawing 2.jpg "alt=" Wkiol1mfmnizrzcmaaqqd84jjmo021.jpg "/>

5. Pointers and Arrays

Pointers provide a way for you to use an address

Initialization of arrays and two-dimensional arrays, pointers and arrays