Make a habit to use Iterative Macro for iterating Data Structure

Iterative_macros/Makefile

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+TARGET: exe
+libdll.a: dll.o
+	ar rs libdll.a dll.o
+dll.o: dll.c
+	gcc -g -c -I . dll.c -o dll.o
+exe: application.o libdll.a
+	gcc -g application.o -o exe -L . -ldll
+application.o: application.c
+	gcc -g -c -I . application.c -o application.o
+clean:
+	rm *.o
+	rm libdll.a
+	rm exe

Iterative_macros/application.c

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+/*
+ * =====================================================================================
+ *
+ *       Filename:  application.c
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 08:05:32 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+#include "dll.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <assert.h>
+
+/*Application specific data structures*/
+typedef struct student_{
+
+    char name[32];
+    int age;
+    int weight;
+    unsigned int rollno;
+} student_t;
+
+static void
+print_student_details(student_t *student){
+
+    printf("Name = %s\n",   student->name);
+    printf("Age = %d\n",    student->age);
+    printf("weight = %d\n", student->weight);
+    printf("rollno = %u\n", student->rollno);
+}
+
+static void
+print_student_db(dll_t *student_db) {
+
+#if 0
+    /*Old Code*/
+    if(!student_db || !student_db->head) return;
+
+    dll_node_t *head = student_db->head;
+    student_t *data = NULL;
+
+    while(head){
+        data = head->data;
+        print_student_details(data);
+        head = head->right;    
+    }
+#endif
+    /*Iterate over DLL using Iterative Macro*/
+    
+    dll_node_t *node_ptr = NULL;
+    student_t *data = NULL;
+
+    ITERATE_LIST_BEGIN(student_db, node_ptr){
+
+        data = node_ptr->data;
+        print_student_details(data);
+    } ITERATE_LIST_END;
+}
+
+/*Application specific data structures*/
+typedef struct employee_{
+
+    char name[32];
+    char designation[32];
+    unsigned int salary;
+    unsigned int emp_id;
+} employee_t;
+
+static void
+print_employee_details(employee_t *employee){
+
+    printf("Name = %s\n",   employee->name);
+    printf("Designation = %s\n",    employee->designation);
+    printf("salary = %u\n", employee->salary);
+    printf("emp_id = %u\n", employee->emp_id);
+}
+
+static void
+print_employee_db(dll_t *student_db) {
+
+    if(!student_db || !student_db->head) return;
+
+    dll_node_t *head = student_db->head;
+    student_t *data = NULL;
+
+    while(head){
+        data = head->data;
+        print_student_details(data);
+        head = head->right;    
+    }
+}
+
+/*Search function*/
+
+student_t *
+search_student_by_rollno(dll_t *student_db, 
+                         unsigned int rollno/*search key*/){
+
+    if(!student_db || !student_db->head) return NULL;
+
+    dll_node_t *head = student_db->head;
+    student_t *data = NULL;
+
+    while(head){
+        data = head->data;
+        if(data->rollno == rollno)
+            return data;
+        head = head->right;    
+    }
+}
+
+
+/*Search function*/
+
+employee_t *
+search_employee_by_emp_id(dll_t *employee_db, 
+                         unsigned int emp_id/*search key*/){
+
+    if(!employee_db || !employee_db->head) return NULL;
+
+    dll_node_t *head = employee_db->head;
+    employee_t *data = NULL;
+
+    while(head){
+        data = head->data;
+        if(data->emp_id == emp_id)
+            return data;
+        head = head->right;    
+    }
+}
+
+/*Search callbacks*/
+static int /*return 0 if matches, return -1 if do not match*/
+search_student_db_by_key(void *data, void *key){
+
+    student_t *student = (student_t *)data;
+    unsigned int rollno = (unsigned int)key;
+    if(student->rollno == rollno)
+        return 0;
+    return -1;
+}
+
+/*Search callbacks*/
+static int /*return 0 if matches, return -1 if do not match*/
+search_employee_db_by_key(void *data, void *key){
+
+    employee_t *emp = (employee_t *)data;
+    unsigned int emp_id = (unsigned int)key;
+    if(emp->emp_id == emp_id)
+        return 0;
+    return -1;
+}
+
+/*Comparion Callback*/
+/*Return 0 if equal,
+ *      -1 if stud1 < stud2
+ *       1 if stud1 > stud2*/
+
+static int
+student_comparison_fn(void *stud1, void *stud2){
+    
+    /*Let us define the sorting order of students, 
+     * Let us compare the students Alphabetically on their names
+     * If two students have same name, younger students should 
+     * come before elder student
+     * If age is also same, lighter student comes before heavier
+     * if Weight is also same, students with numerically lesser rollno
+     * comes before in the DLL*/
+    
+     student_t *student1 = (student_t *)stud1;
+     student_t *student2 = (student_t *)stud2;
+
+     if(strncmp(student1->name, student2->name, 32) < 0)
+         return -1;
+     else if(strncmp(student1->name, student2->name, 32) > 0)
+         return 1;
+     else if(student1->age < student2->age)
+         return -1;
+     else if(student1->age > student2->age)
+         return 1;
+     else if(student1->weight < student2->weight)
+         return -1;
+     else if(student1->weight > student2->weight)
+         return 1;
+     else if(student1->rollno < student2->rollno)
+         return -1;
+     else if(student1->rollno > student2->rollno)
+         return 1;
+     assert(0); /*intentionally Crash the program !!*/
+}
+
+int 
+main(int argc, char **argv){
+
+    /*Student database*/
+    student_t *student1 = calloc(1, sizeof(student_t));
+    strncpy(student1->name, "Abhishek", strlen("Abhishek"));
+    student1->age = 31;
+    student1->weight = 75;
+    student1->rollno = 800000;
+
+    student_t *student2 = calloc(1, sizeof(student_t));
+    strncpy(student2->name, "Joseph", strlen("Joseph"));
+    student2->age = 41;
+    student2->weight = 70;
+    student2->rollno = 800400;
+
+    student_t *student3 = calloc(1, sizeof(student_t));
+    strncpy(student3->name, "Jack", strlen("Jack"));
+    student3->age = 29;
+    student3->weight = 55;
+    student3->rollno = 800400;
+    
+    student_t *student4 = calloc(1, sizeof(student_t));
+    strncpy(student3->name, "Abhishek", strlen("Abhishek"));
+    student3->age = 29;
+    student3->weight = 55;
+    student3->rollno = 800399;
+
+    /*Create a new Linked List*/
+
+    dll_t *student_db = get_new_dll();
+    register_key_match_callback(student_db, search_student_db_by_key);
+    register_comparison_callback(student_db, student_comparison_fn);
+    dll_priority_insert_data(student_db, student1);
+    dll_priority_insert_data(student_db, student2);
+    dll_priority_insert_data(student_db, student3);
+#if 0
+    //student_t *student = search_student_by_rollno(student_db, 800400);
+    student_t *student = dll_search_by_key(student_db, (void *)800400);
+    if(!student){
+        printf("Student record not found\n");
+    }
+    else{
+        print_student_details(student);    
+    }
+#endif
+    printf("Printing Stduents list\n");
+    print_student_db(student_db);
+    
+#if 0
+    /*Employee database*/
+    employee_t *employee1 = calloc(1, sizeof(employee_t));
+    strncpy(employee1->name, "Harsh", strlen("Harsh"));
+    strncpy(employee1->designation, "Vice President", strlen("Vice President"));
+    employee1->salary = 11131;
+    employee1->emp_id = 10000;
+
+    employee_t *employee2 = calloc(1, sizeof(employee_t));
+    strncpy(employee2->name, "Huma", strlen("Huma"));
+    strncpy(employee2->designation, "CEO", strlen("CEO"));
+    employee1->salary = 127000;
+    employee1->emp_id = 10001;
+
+    employee_t *employee3 = calloc(1, sizeof(employee_t));
+    strncpy(employee3->name, "Neena", strlen("Neena"));
+    strncpy(employee2->designation, "Manager", strlen("Manager"));
+    employee1->salary = 139000;
+    employee1->emp_id = 10002;
+
+    /*Create a new Linked List*/
+
+    dll_t *employee_db = get_new_dll();
+    register_key_match_callback(employee_db, search_employee_db_by_key);
+    register_comparison_callback(employee_db, student_comparison_fn);
+
+    add_data_to_dll(employee_db, employee1);
+    add_data_to_dll(employee_db, employee2);
+    add_data_to_dll(employee_db, employee3);
+
+    employee_t *employee = dll_search_by_key(employee_db, (void *)10002);
+    if(!employee){
+        printf("Student record not found\n");
+    }
+    else{
+        print_employee_details(employee);    
+    }
+#endif
+    return 0;
+}

Iterative_macros/dll.c

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+/*
+ * =====================================================================================
+ *
+ *       Filename:  dll.c
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 08:04:39 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+#include "dll.h"
+#include <memory.h>
+#include <stdlib.h>
+
+/* Public Function Implementation to create and return
+ * new empty doubly linked list*/
+
+dll_t *
+get_new_dll(){
+
+    dll_t *dll = calloc(1, sizeof(dll_t));
+    dll->head = NULL;
+    dll->key_match = NULL;
+    return dll;
+}
+
+void
+register_key_match_callback(dll_t *dll, 
+                             int (*key_match)(void *, void *)){
+
+    dll->key_match = key_match;
+}
+
+void
+register_comparison_callback(dll_t *dll,
+                            int (*comparison_cb)(void *, void *)){
+
+    dll->comparison_fn = comparison_cb;
+}
+
+/*Generic Search function*/
+void *
+dll_search_by_key (dll_t *dll, void *key){
+
+    if(!dll || !dll->head) return NULL;
+
+    dll_node_t *head = dll->head;
+
+    while(head){
+        if(dll->key_match(head->data, key) == 0)
+            return (void *)head->data;
+        head = head->right;
+    }
+    return NULL;
+}
+
+/*Return 0 - on success
+ *       -1 on Failure*/
+int
+dll_priority_insert_data (dll_t *dll, void *data){
+
+    if(!dll)
+        return -1;
+
+    /*if DLL is empty*/
+    if(!dll->head){
+        add_data_to_dll(dll, data);
+        return 0;
+    }
+
+    dll_node_t *data_node = calloc(1, sizeof(dll_node_t));
+    data_node->data = data;
+    data_node->left = NULL;
+    data_node->right = NULL;
+
+    /* if there is only one node in DLL*/
+    if(dll->head && !dll->head->right){
+        if(dll->comparison_fn(dll->head->data, data) == -1){
+            dll->head->right = data_node;
+            data_node->left = dll->head;
+        }
+        else{
+            dll->head->left = data_node;
+            data_node->right = dll->head;
+            dll->head = data_node;
+        }
+        return 0;
+    }
+
+    /*if More than one node in DLL*/
+    if(dll->comparison_fn(data, dll->head->data) == -1){
+        data_node->right = dll->head;
+        dll->head->left = data_node;
+        dll->head = data_node;
+        return 0;
+    }
+
+    dll_node_t *prev = NULL,
+               *curr = NULL;
+
+    curr = dll->head;
+
+    while(curr){
+        if(dll->comparison_fn(data, curr->data) != -1){
+            prev = curr;
+            curr = curr->right;
+            continue;
+        }
+
+        prev->right = data_node;
+        data_node->left = prev;
+        data_node->right = curr;
+        curr->left = data_node;
+        return 0;
+    }
+
+    /*Add in the end*/
+    prev->right = data_node;
+    data_node->left = prev;
+    return 0;
+}
+
+/* Public Function Implementation to add a new application
+ *  * data to DLL */
+int
+add_data_to_dll (dll_t *dll, void *app_data){
+
+    if(!dll || !app_data) return -1;
+    
+    dll_node_t *dll_new_node = calloc(1, sizeof(dll_node_t));
+    dll_new_node->left = NULL;
+    dll_new_node->right = NULL;
+    dll_new_node->data = app_data;
+
+    /*Now add this to the front of DLL*/
+    if(!dll->head){
+        dll->head = dll_new_node;
+        return 0;
+    }
+
+    dll_node_t *first_node = dll->head;
+    dll_new_node->right = first_node;
+    first_node->left = dll_new_node;
+    dll->head = dll_new_node;
+    return 0;
+}
+

Iterative_macros/dll.h

@@ -0,0 +1,68 @@
+/*
+ * =====================================================================================
+ *
+ *       Filename:  dll.h
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 08:03:38 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+/*Header file for Doubly Linked List*/
+
+typedef struct dll_node_{
+
+    void *data;
+    struct dll_node_ *left;
+    struct dll_node_ *right;
+} dll_node_t;
+
+typedef struct dll_{
+    dll_node_t *head;
+    int (*key_match)(void *, void *);
+    int (*comparison_fn)(void *, void *);
+} dll_t;
+
+void
+register_key_match_callback(dll_t *dll, int (*key_match)(void *, void *));
+
+void
+register_comparison_callback(dll_t *dll, int (*comparison_cb)(void *, void *));
+
+/*Generic Search function*/
+void *
+dll_search_by_key (dll_t *dll, void *key);
+
+int
+dll_priority_insert_data (dll_t *dll, void *data);
+
+/* Public Function declaration to create and return
+ * a new empty doubly linked list*/
+dll_t *
+get_new_dll();
+
+/*  Public Function declaration to add the appication
+ *  data to DLL*/
+int
+add_data_to_dll(dll_t *dll, void *appn_data);
+
+/*Macro to iterate over a DLL*/
+
+#define ITERATE_LIST_BEGIN(list_ptr, node_ptr)                              \
+{                                                                           \
+    dll_node_t *_node_ptr = NULL;                                           \
+    node_ptr = list_ptr->head;                                              \
+    for(; node_ptr!= NULL; node_ptr = _node_ptr){                           \
+        if(!node_ptr) break;                                                \
+        _node_ptr = node_ptr->right;
+
+#define ITERATE_LIST_END  }}
+

Iterative_macros/tree.c

@@ -0,0 +1,153 @@
+/*
+ * =====================================================================================
+ *
+ *       Filename:  tree.c
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 09:51:42 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+#include "tree.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+
+tree_t*
+init_tree(void)
+{
+    tree_t *tree = calloc(1,sizeof(tree_t));
+    if(!tree)
+        return NULL;
+    tree->root = NULL;
+    return tree;
+}
+
+tree_node_t* init_tree_node(int n)
+{
+    tree_node_t *node = calloc(1, sizeof(tree_node_t));
+    if(!node)   return NULL;
+    node->data = n;
+    return node;
+}
+
+int
+add_tree_node_by_value(tree_t *tree, int n)
+{
+    tree_node_t *root = NULL, *parent = NULL;;
+    if(!tree) return -1;
+    tree_node_t *node = init_tree_node(n);
+    if(!tree->root){
+        tree->root = node;
+        return 0;
+    }
+
+    root = tree->root;
+
+    while(root){
+        parent = root;
+        root = (n <= root->data) ? root->left : root->right;
+    } // while ends
+
+    if(n <= parent->data)
+        parent->left = node;
+    else
+        parent->right = node;
+
+    node->parent = parent;
+    return 0;
+}
+
+tree_node_t *
+get_left_most(tree_node_t *node){
+
+    if(!node->left)
+        return NULL;
+
+    while(node->left){
+        node = node->left;
+    }
+    return node;
+}
+
+tree_node_t *
+get_next_inorder_succ(tree_node_t *node){
+
+    /* case 1 : Handling root*/
+    if(!node->parent){
+        if(node->right){
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+        }
+        return NULL;
+    }
+
+    /*case 2 : if node is a left child of its parent*/
+    if(node == node->parent->left){
+        if(!node->right)
+            return node->parent;
+        else
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+    }
+
+    /*case 3 : if node is a right child of its parent*/
+    if(node == node->parent->right){
+        if(node->right){
+            if(node->right->left)
+                return get_left_most(node->right);
+            else
+                return node->right;
+        }
+    }
+
+    /* case 4 : Inorder successor of node is a ancestor whose
+     * left children is also an ancestor*/
+
+    tree_node_t *gp = node->parent->parent;
+    tree_node_t *parent = node->parent;
+
+    while(gp && gp->left != parent){
+
+        parent = gp;
+        gp = gp->parent;
+    }
+
+    return gp;
+}
+
+int
+main(int argc, char **argv){
+
+    tree_t *tree = init_tree();
+
+    add_tree_node_by_value(tree,  100);
+    add_tree_node_by_value(tree,  50);
+    add_tree_node_by_value(tree,  10);
+    add_tree_node_by_value(tree,  90);
+    add_tree_node_by_value(tree,  95);
+    add_tree_node_by_value(tree,  99);
+    
+    tree_node_t *treenodeptr = NULL;
+
+    ITERATE_BST_BEGIN(tree, treenodeptr){
+    
+        printf("%u ", treenodeptr->data);
+
+    } ITERATE_BST_END;
+    printf("\n");
+    
+    return 0;
+}

Iterative_macros/tree.h

@@ -0,0 +1,58 @@
+/*
+ * =====================================================================================
+ *
+ *       Filename:  tree.h
+ *
+ *    Description:  
+ *
+ *        Version:  1.0
+ *        Created:  05/02/24 09:52:32 PM IST
+ *       Revision:  none
+ *       Compiler:  gcc
+ *
+ *         Author:  YOUR NAME (), 
+ *   Organization:  
+ *
+ * =====================================================================================
+ */
+
+#ifndef __TREE__
+#define __TREE__
+
+typedef struct tree_node {
+    struct tree_node *left;
+    struct tree_node *right;
+    struct tree_node *parent;
+    int data;
+} tree_node_t;
+
+
+typedef struct tree {
+    tree_node_t *root;
+} tree_t;
+
+int
+add_tree_node_by_value(tree_t *tree, int n);
+
+tree_t* init_tree(void);
+
+tree_node_t* init_tree_node(int n);
+
+/*Pre-requisites functions to write iterative
+ * macros for a tree.*/
+
+tree_node_t *
+get_left_most (tree_node_t *node);
+
+tree_node_t *
+get_next_inorder_succ (tree_node_t *node);
+
+#define ITERATE_BST_BEGIN(treeptr, currentnodeptr)            \
+{                                                             \
+    tree_node_t *_next = NULL;                                \
+    for(currentnodeptr = get_left_most(treeptr->root); currentnodeptr != NULL ; currentnodeptr = _next){    \
+                        _next = get_next_inorder_succ(currentnodeptr);
+
+#define ITERATE_BST_END }}
+
+#endif