I am now doing the basic operations of a single linked list, but call the Print function can only output the latest the value of the incoming Set function can't Print all, is what happened, please?
Such as input 1 Alice 10001 input 1 Sam 10009 then enter 1 2, William, 10010 in the input can only output the latest input content, but how also can not find a reason, to feel your own code do not have what problem

 # include 
#include 
#include 
Typedef struct student {
int data; 
char name[20]; 
Struct student * next; 
}node; 
* Set the node (the node * head, node * p);//in the end of the insert node p 
Void Print (node * head);//print out all the node 
* Insert node (the node * head, node * p, int n);//behind the NTH insert 
Head node * Del (node * and an int data);//delete student id data node 
Int Length (node * head); Length//o 
Node * Sort (node * head);//in accordance with the data ascending order 
Int main () 
{
Int choice, num, l, n; 
Char r [20]; 
The head node *=NULL; 
Node * p=(*) malloc (sizeof (node)); 
Printf (" Select: \ n1. Set \ n2 Print, \ n3 Insert, \ n4 interchange, Delete \ n5 GetLength, \ n6 Sort. \ n "); 
The scanf (" % d ", & amp; Choice); 
While (choice>=1 & amp; & Choice
=6){
The switch (choice) {
Case 1: printf (" Enter the name and data: \ n "); 
The scanf (" % s % d ", r, & amp; Num); 
Strcpy (p - & gt; The name, r); 
P - & gt; data=https://bbs.csdn.net/topics/num; 
The head=Set (head, p); 
break; 
Case 2: Print (the head); break; 
Case 3: printf (" Enter the name and data: \ n "); 
The scanf (" % s % d ", r, & amp; Num); 
Strcpy (p - & gt; The name, r); 
P - & gt; data=https://bbs.csdn.net/topics/num; 
Printf (" Enter the location: \ n "); 
The scanf (" % d ", & amp; n); 
The head=Insert (head, p, n); break; 
Case 4: printf (" Enter data: \ n "); 
The scanf (" % d ", & amp; Num); 
The head=Del (head, num); break; 
Case 5: l=Length (the head); Printf (" Length=% d \ n "); break; 
Case 6: head=Sort (head); break; 
Default:; break; 

} 
Printf (" Select: \ n1. Set \ n2 Print, \ n3 Insert, \ n4 interchange, Delete \ n5 GetLength, \ n6 Sort. \ n "); 
The scanf (" % d ", & amp; Choice); 
} 
return 0; 
} 
Node * Set (node * head, node * p)//in the end insert node p 
{
Node * PTR. 
If (head==NULL) {
The head=p; 
The head - & gt; Next=head; 
} 
The else {
PTR=head; 
While (PTR - & gt; Next!=head) 
{
PTR=PTR - & gt; Next; 
} 
/* find tail */
P - & gt; Next=head; 
PTR - & gt; Next=p; 
} 
Return the head; 
} 
Void Print (node * head) 
{
Node * PTR=head; 
If (head==NULL) {
Printf (" No records \ n "); 
} 
The else {
Printf (" % d % s \ n ", the head - & gt; The data, the head - & gt; Name); 
PTR=PTR - & gt; Next; 
for(; PTR!=the head; PTR=PTR - & gt; Next) 
{
Printf (" % d % s \ n ", PTR - & gt; The data, the PTR - & gt; Name); 
} 
} 
} 
* Insert node (the node * head, node * p, int n)//behind the NTH node Insert the value of the p n> 0 
{
Node * q=head; 
int i=1; 
If (head==NULL) {
Always Insert a printf (" \ n "); 
} the else 
{
While (q - & gt; Next!=head& & i{
Q=q - & gt; Next; 
i++; 
} 
If (I==n) {
The node * r=q - & gt; Next; 
P - & gt; Next=r; 
Q - & gt; Next=p; 
} else {
Always Insert a printf (" \ n "); 
} 
} 
Return the head; 
} 
Head node * Del (node * and an int data)//delete student id for the data node 
{
If ((head==NULL) & amp; & (the head - & gt; Next==head& & The head - & gt; The data!=data)) 
{
Always delete a printf (" \ n "); 
} else if (head - & gt; Next==head& & The head - & gt; data=https://bbs.csdn.net/topics/=data) {
Free (the head); 
} else {
Node * (p1, p2, 
Int flag=1; 
P1=head; 
The p2=p1 - & gt; Next; 
If (p1 - & gt; data=https://bbs.csdn.net/topics/=data) 
{
While (p2 - & gt; Next!=head) 
{
The p2=p2 - & gt; Next; 
}//p2 tail 
The head=head - & gt; Next; 
The p2 - & gt; Next=head; 
Free (p1); 
} 
The else 
{
for(; The p2!=the head; P1=p1 - & gt; Next) {
If (p2 - & gt; data=https://bbs.csdn.net/topics/=data) {
flag=0; 
P1 - & gt; Next=p2 - & gt; Next; 
Free (p2); 
break; 
} 
The p2=p2 - & gt; Next; 
} 
If (flag==1) {
Always delete a printf (" \ n "); 
} 
} 
} 
Return the head; 
} 
Int Length (node * head) {
Int count; 
Node * p; 
If (head==NULL) {
Count=0; 
} else if (head - & gt; Next==head) 
{
Count=1; 
} the else 
{
Count=1; 
For (p=head - & gt; Next; p!=the head; P=p - & gt; Next) 
{
count++; 
} 
} 
return count; 
} 
Node * Sort (node * head)//in accordance with the student id ascending order 
{
Int t; 
Char STR [20]. 
Node * I=head, * j=head; 
If (head==NULL | | (head - & gt; Next==head)) {//a single node 
Return the head; 
} 
The else {
For (I=head; I - & gt; Next!=the head; I=I - & gt; Next) {
For (j=head; J - & gt; Next!=the head; J=j - & gt; Next) {
If ((j - & gt; Data) & gt; (j - & gt; Next - & gt; Data)) 
{
T=j - & gt; data; J - & gt; data=https://bbs.csdn.net/topics/j-> next -> data; J -> next -> data=t; 
Strcpy (STR, j - & gt; Name); 
Strcpy (j - & gt; The name, j - & gt; Next - & gt; Name); 
Strcpy (j - & gt; Next - & gt; The name, STR); 
} 
} 
} 
Return the head; 
} 
} 

CodePudding user response:

Why so many code? To input and print

CodePudding user response:

Now don't have to malloc list insert when allocating memory delete released when free memory? -- -- -- -- --

CodePudding user response:

Code too much, I also didn't watch carefully to see where your insert didn't see you allocated memory you just at the beginning of the main function are assigned a node in the structure of the body you want in each time you insert the malloc allocation a memorynullnullnullnullnullnullnullnullnullnullnullnullnullnullnull