initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
../src/yongqiang.c:29:15: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
1. Node *head = root;
//============================================================================
// Name : typedef - struct
// Author : Yongqiang Cheng
// Version : Version 1.0.0
// Copyright : Copyright (c) 2019 Yongqiang Cheng
// Description : Hello World in C++, Ansi-style
//============================================================================
/*
** Insert into an ordered, singly linked list. The arguments are
** a pointer to the first node in the list, and the value to insert.
*/
#include <stdio.h>
#include <stdlib.h>
#define FALSE 1
#define TRUE 0
typedef struct NODE
{
struct NODE *link;
int value;
} Node;
// This function prints contents of linked list starting from the given node.
int sll_display(const Node *root)
{
Node *head = root;
if (NULL == root)
{
return FALSE;
}
printf("\n[ ");
while (NULL != head)
{
printf("%d ", head->value);
head = head->link;
}
printf("]");
return TRUE;
}
int sll_insert(Node **rootp, int new_value)
{
Node *current;
Node *previous;
Node *new_node;
if (NULL == rootp)
{
return FALSE;
}
/*
** Get the pointer to the first node.
*/
current = *rootp;
previous = NULL;
/*
** Look for the right place by walking down the list
** until we reach a node whose value is greater than or equal to the new value.
*/
while ((NULL != current) && (current->value < new_value))
{
previous = current;
current = current->link;
}
/*
** Allocate a new node and store the new value into it.
** In this event, we return FALSE.
*/
new_node = (Node *) malloc(sizeof(Node));
if (NULL == new_node)
{
return FALSE;
}
new_node->value = new_value;
/*
** Insert the new node into the list, and return TRUE.
*/
new_node->link = current;
if (NULL == previous)
{
*rootp = new_node;
}
else
{
previous->link = new_node;
}
return TRUE;
}
int main()
{
Node *root = NULL;
int result = 0;
int ret = 0;
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 5);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 10);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 15);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 9);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 12);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 0);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 20);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
return TRUE;
}
16:47:30 **** Build of configuration Debug for project yongqiang_example ****
make all
Building file: ../src/yongqiang.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/yongqiang.d" -MT"src/yongqiang.o" -o "src/yongqiang.o" "../src/yongqiang.c"
../src/yongqiang.c: In function ‘sll_display’:
../src/yongqiang.c:29:15: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
Node *head = root;
^
Finished building: ../src/yongqiang.c
Building target: yongqiang_example
Invoking: GCC C Linker
gcc -o "yongqiang_example" ./src/yongqiang.o
Finished building target: yongqiang_example
16:47:31 Build Finished (took 595ms)
NULL pointer.
[ 5 ]
[ 5 10 ]
[ 5 10 15 ]
[ 5 9 10 15 ]
[ 5 9 10 12 15 ]
[ 0 5 9 10 12 15 ]
[ 0 5 9 10 12 15 20 ]
2. const Node *head = root;
//============================================================================
// Name : typedef - struct
// Author : Yongqiang Cheng
// Version : Version 1.0.0
// Copyright : Copyright (c) 2019 Yongqiang Cheng
// Description : Hello World in C++, Ansi-style
//============================================================================
/*
** Insert into an ordered, singly linked list. The arguments are
** a pointer to the first node in the list, and the value to insert.
*/
#include <stdio.h>
#include <stdlib.h>
#define FALSE 1
#define TRUE 0
typedef struct NODE
{
struct NODE *link;
int value;
} Node;
// This function prints contents of linked list starting from the given node.
int sll_display(const Node *root)
{
const Node *head = root;
if (NULL == root)
{
return FALSE;
}
printf("\n[ ");
while (NULL != head)
{
printf("%d ", head->value);
head = head->link;
}
printf("]");
return TRUE;
}
int sll_insert(Node **rootp, int new_value)
{
Node *current;
Node *previous;
Node *new_node;
if (NULL == rootp)
{
return FALSE;
}
/*
** Get the pointer to the first node.
*/
current = *rootp;
previous = NULL;
/*
** Look for the right place by walking down the list
** until we reach a node whose value is greater than or equal to the new value.
*/
while ((NULL != current) && (current->value < new_value))
{
previous = current;
current = current->link;
}
/*
** Allocate a new node and store the new value into it.
** In this event, we return FALSE.
*/
new_node = (Node *) malloc(sizeof(Node));
if (NULL == new_node)
{
return FALSE;
}
new_node->value = new_value;
/*
** Insert the new node into the list, and return TRUE.
*/
new_node->link = current;
if (NULL == previous)
{
*rootp = new_node;
}
else
{
previous->link = new_node;
}
return TRUE;
}
int main()
{
Node *root = NULL;
int result = 0;
int ret = 0;
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 5);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 10);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 15);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 9);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 12);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 0);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
result = sll_insert(&root, 20);
if (result)
{
printf("Failed to insert element.");
}
ret = sll_display(root);
if (ret)
{
printf("NULL pointer.");
}
return TRUE;
}
16:44:22 **** Build of configuration Debug for project yongqiang_example ****
make all
Building file: ../src/yongqiang.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/yongqiang.d" -MT"src/yongqiang.o" -o "src/yongqiang.o" "../src/yongqiang.c"
Finished building: ../src/yongqiang.c
Building target: yongqiang_example
Invoking: GCC C Linker
gcc -o "yongqiang_example" ./src/yongqiang.o
Finished building target: yongqiang_example
16:44:23 Build Finished (took 602ms)
NULL pointer.
[ 5 ]
[ 5 10 ]
[ 5 10 15 ]
[ 5 9 10 15 ]
[ 5 9 10 12 15 ]
[ 0 5 9 10 12 15 ]
[ 0 5 9 10 12 15 20 ]
