C提高_day03_玩轉多級指標

標籤：

#include <stdlib.h>#include <string.h>#include <stdio.h>char **getMem51(int num){    int i = 0;    char **p2 = NULL;    p2 = (char **)malloc(sizeof(char *) * num);    if (p2 == NULL)    {        return NULL;    }    for (i=0; i<num; i++)    {        p2[i] = (char *)malloc(sizeof(char)  * 100  ); //char buf[100];        sprintf(p2[i], "%d%d%d", i+1, i+1, i+1);    }    return p2;}int getMem52(char ***p3 , int num){    int i = 0;    char **tmp = NULL;    if (p3 == NULL)  //判斷p3 而不是*p3.  p3指向的記憶體空間可以是NULL     {        return -1;    }        tmp = (char **)malloc(sizeof(char *) * num);    if (tmp == NULL)    {        return NULL;    }    for (i=0; i<num; i++)    {        tmp[i] = (char *)malloc(sizeof(char)  * 100  ); //char buf[100];        sprintf(tmp[i], "%d%d%d", i+1, i+1, i+1);    }    *p3 = tmp;     //1 2    return 0;}void getMem52_Free(char ***p3 , int num){    int i = 0;    char **tmp = NULL;    if (p3 == NULL)    {        return ;    }    tmp = *p3;     for (i=0; i<num; i++)    {        free(tmp[i]);    }    free(tmp);         *p3 = NULL; //把實參賦值成null}void main(){    int i = 0, j = 0;    char **p2 = NULL;    int num = 5;    //p2 = getMem51(num);    getMem52(&p2, num);    for (i=0; i<num; i++)    {        printf("%s \n", p2[i]);    }    getMem52_Free(&p2, num);    printf("hello...\n");    system("pause");    return ;}

C提高_day03_玩轉多級指標