Pointer: Memory Model 3; pointer model 3

Pointer: Memory Model 3; pointer model 3

 

1 # define _ CRT_SECURE_NO_WARNINGS 2 # include <stdio. h> 3 # include <stdlib. h> 4 # include <string. h> 5 6 // generate malloc 7 char ** getMem41 (int num) 8 {9 char ** p2 = NULL; 10 int I = 0; 11 12 p2 = (char **) malloc (sizeof (char *) * num); 13 if (p2 = NULL) 14 {15 return NULL; 16} 17 for (I = 0; I <num; I ++) 18 {19 p2 [I] = (char *) malloc (sizeof (char) * 100 ); // char buf [100]; 20 sprintf (p2 [I], "% d", I + 1, I + 1, I + 1); // in this format ("% d", I + 1, I + 1, I + 1) print to p2 [I]; 21} 22 return p2; 23} 24 25 // sort 26 void sortNum31 (char ** array, int num) 27 {28 char * tmp = NULL; 29 int I = 0, j = 0; 30 for (I = 0; I <num; I ++) 31 {32 for (j = I; j <num; j ++) 33 {34 if (strcmp (array [I], array [j]) <0) 35 {36 tmp = array [I]; // note: the value of the exchanged data, the pointer is switched // the pointer is directed to 37 array [I] = array [j]; 38 array [j] = tmp; 39} 40} 41} 42} 43 44 // print 45 46 void printNum31 (char ** array, int num) 47 {48 int I = 0; 49 for (I = 0; I <num; I ++) 50 {51 printf ("% s", array [I]); 52} 53} 54 55 void getMem41_Free (char ** p, int num) 56 {57 int I = 0; 58 char ** p2 = p; 59 for (I = 0; I <num; I ++) 60 {61 if (p2 [I]! = NULL) 62 {63 free (p2 [I]); 64 p2 [I] = NULL; 65} 66} 67 if (p2! = NULL) 68 {69 free (p2); 70 p2 = NULL; 71} 72} 73 74 int main () 75 {76 int I = 0; 77 char ** p2; 78 int num = 5; 79 char * tmp = NULL; 80 char tmpBuf [100]; 81 82 p2 = getMem41 (num ); 83 84 // print 85 printf before sorting ("Before sorting: \ n"); 86/* for (I = 0; I <num; I ++) 87 {88 printf ("% s \ n", p2 [I]); 89} */90 printNum31 (p2, num ); 91 92 93 // sort // the pointer 94/* for (I = 0; I <num; I ++) 95 {96 for (int j = I + 1; j <num; j ++) 97 {98 if (strcmp (p2 [I], p2 [j]) <0) 99 {100 tmp = p2 [I]; 101 p2 [I] = p2 [j]; 102 p2 [j] = tmp; 103} 104} 105} */106 107 108 // sort // swap memory 109/* for (I = 0; I <num; I ++) 110 {111 for (int j = I + 1; j <num; j ++) 112 {113 if (strcmp (p2 [I], p2 [j]) <0) 114 {115 strcpy (tmpBuf, p2 [I]); 116 strcpy (p2 [I], p2 [j]); 117 strcpy (p2 [j], tmpBuf ); 118} 119} 120} */121 122 // sorting 123 sortNum31 (p2, num); 124 // sorting 125 printf ("\ n sorted: \ n "); 126/* for (I = 0; I <num; I ++) 127 {128 printf ("% s \ n", p2 [I]); 129} */130 printNum31 (p2, num); 131 // release memory 132 getMem41_Free (p2, num); 133 system ("pause"); 134 return 0; 135}