add c_pointer_sample for wechat group

c_pointer_sample_for_students.c

@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_STUDENTS_NUM 100
+
+typedef struct {
+    char name[21];
+    int age;
+    char addr[101];
+} student_t;
+
+typedef struct {
+    student_t stu[MAX_STUDENTS_NUM];
+    int index;
+} studentList_t;
+
+int initList_example(studentList_t **students)
+{
+    studentList_t *newList = (studentList_t *)malloc(sizeof (studentList_t));
+    if (newList == NULL) {
+        return -1;
+    }
+
+    memset(newList, 0, sizeof (studentList_t));
+    *students = newList;
+    return 0;
+}
+
+void initList_proc_example()
+{
+    studentList_t *students;
+    if (initList_example(&students)) {
+        printf("init error!\n");
+        return;
+    }
+    printf("init ok.\n");
+}
+
+void initList_suggestion1(studentList_t *students)
+{
+    students->index = 0;
+    memset(students->stu, 0, sizeof (student_t) * MAX_STUDENTS_NUM);
+}
+
+void initList_proc_suggestion1()
+{
+    studentList_t students;
+    initList_suggestion1(&students);
+}
+
+studentList_t *initList_suggestion2()
+{
+    studentList_t *newList = (studentList_t *)malloc(sizeof (studentList_t));
+    if (newList == NULL) {
+        return NULL;
+    }
+
+    memset(newList, 0, sizeof (studentList_t));
+    return newList;
+}
+
+void initList_proc_suggestion2()
+{
+    studentList_t *students = initList_suggestion2();
+    if (students == NULL) {
+        printf("init error!\n");
+        return;
+    }
+    printf("init ok.\n");
+}
+
+typedef struct _studentLink_t {
+    struct _studentLink_t *next;
+    student_t info;
+} studentLink_t;
+
+int initLink_example(studentLink_t **node)
+{
+    studentLink_t *newNode = (studentLink_t *)malloc(sizeof (studentLink_t));
+    if (newNode == NULL) {
+        return -1;
+    }
+
+    newNode->next = NULL;
+    *node = newNode;
+    return 0;
+}
+
+void initLink_proc_example()
+{
+    studentLink_t *link;
+    if (initLink_example(&link)) {
+        printf("init error!\n");
+        return;
+    }
+
+    printf("init ok.\n");
+}
+
+studentLink_t *initLink_suggestion()
+{
+    studentLink_t *newNode = (studentLink_t *)malloc(sizeof (studentLink_t));
+    if (newNode == NULL) {
+        return NULL;
+    }
+
+    newNode->next = NULL;
+    return newNode;
+}
+
+void initLink_proc_suggestion()
+{
+    studentLink_t *studentsLink = initLink_suggestion();
+    if (studentsLink == NULL) {
+        printf("init error!\n");
+        return;
+    }
+    printf("init ok.\n");
+}