"C + + Institute" (3) two-dimensional array/Two-point lookup method/pointer/module injection

1. Two-dimensional array

A two-dimensional array can be used as a one-dimensional array, and each element is a one-dimensional array.

#include <stdio.h> #include <stdlib.h>void main () {    int a[3][4] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; for    (int i = 0; i < 3; i++)    {        for (int j = 0; J < 4; j + +)        {            printf ("%d,%d,%d,%x,%x   ", A[i][j], * (A[i] + j), * (&a[i][j]), &a I [j],a[i]+j);        }        printf ("\ n");    }    A[x], which represents the first address of an element in line X, the hand address of this array in a row,    printf ("\n\na[0]=%x,a[1]=%x,a[2]=%x", A[0], a[1], a[2]);    System ("Pause");}  

2. Two-point lookup method

While/for two ways to achieve

#define _crt_secure_no_warnings#include <stdio.h> #include <stdlib.h>void showarray (int a[], int n) {for ( int i = 0; I < n; i++) {printf ("%d,", A[i]);} printf ("\ n");} void Paixu (int a[], int n) {for (int i = 0; i < n-1; i++) {for (int j = 0; J < n-1-I; k + +) {if (a[j]>a[j+1]) {i NT TEMP = A[j];a[j] = a[j + 1];a[j + 1] = temp;}}} Num is the data to be looked up, returning the array subscript int searchfor (int a[], int n, int num) {for (int tou = 0, Wei = n-1, Zhong = (tou + wei)/2; Tou &lt ; = Wei; zhong= (Tou+wei)/2) {printf ("\ n start looking for%d,%d,%d", Tou, Wei, Zhong), if (a[zhong] = = num) {return zhong;} else if (a[zhong]>num) {wei = zhong-1;} Else{tou = zhong + 1;}}} int searchwhile (int a[], int n, int num) {int tou = 0;int Wei = n-1;int zhong = (tou + wei)/2;while (Tou <= wei) {pri NTF ("\ n start looking for%d,%d,%d", Tou, Wei, Zhong), if (a[zhong] = = num) {return zhong;} else if (a[zhong]>num) {Wei = Zhong-1;zhong = (tou + wei)/2;} Else{tou = zhong + 1;zhong = (tou + wei)/2;}}} void Main () {int a[50] = {0};time_t ts;srand ((unsigned int) time (&ts));//random number seed for (int i = 0; i <; i++) {A[i] = rand ()% 100;//printf ("%d,", A[i]);} Paixu (A, 50); Showarray (A, +), int num;printf ("plesae input your Find num:"), scanf ("%d", &num);//scan data receive input//int ret = Searchfor (A, 5 0, num); int ret = Searchwhile (A, A, num), if (ret = =-1) {printf ("not find\n");} else{printf ("Find [%d]\n", A[ret]);} System ("Pause");}

3. Pointers, function pointers

normal pointer, variable address, function pointers, The function address.

void (*P1) () = (void (*) ()) 0x2a1118;//function address 0x2a1118
P1 ();

#include <stdio.h> #include <stdlib.h>int add (int a, int b) {return a + B;} void Main () {int n = 100;int *p = &n;*p = 50;printf ("%d\n", n), int (*PF) (int, int);//function pointer pf = add;printf ("%d\n", pf (3, 5 ); System ("Pause");}

second-level pointers;

#include <stdio.h> #include <stdlib.h>char a = ' a '; char b = ' B '; char c = ' C '; void change (char **pp) {    *pp = &b;    **pp = ' D ';} void Main () {    char *p = &a;    printf ("My rank is: [%c]\n", *p);    Change (&p);    printf ("My rank is: [%c]\n", *p);    

4. Module injection

DllInject.exe Tools

_declspec (dllexport) void Go ()//export as DLL module;

Target procedure;

#include <stdio.h> #include <stdlib.h> #include <windows.h>char a = ' a '; char b = ' B '; char c = ' C '; void Mai N () {char *p = Null;p = &a;printf ("p=%x,&a=%x,&b=%x,&c=%x\n", p, &a, &b, &c); while (1) {printf ("My rank is: [%c]\n", *p); Sleep (10000);//10s}}

Plug-in module;

_declspec (dllexport) void Go ()//export to DLL module; {Char **pp = (char * *) 0x288000;//get p address *pp = (char *) 0x288002;//level C address}

"C + + Institute" (3) two-dimensional array/Two-point lookup method/pointer/module injection