Question

This program uses C++. This program reads in a line from the user and prints it out in a certain format. An example would be Input: 1 2 3 4 5 would result Output: [{1}, {2}, {3}, {4}, {5}]. When quotations marks are added into the input the format becomes different. For instance, Input 1 2 "3 4 5" would result in [{1}, {2}, {3 4 5}]. When I ad multiple quotation marks into the input, it will only use the last portion in quotations. For instance, Input 1 "2 3" 4 "5 6" would result in [{1}, {5 6}, {4}, {5 6}] instead of  [{1}, {2 3}, {4}, {5 6}]. Any help in getting it to print the latter? To compile the program use -lreadline.

#include <stdio.h>
#include <cstring>
#include <iostream>
#include <string>
#include <ctype.h>
#include <malloc.h>
#include <readline/readline.h>
#include <readline/history.h>

using namespace std;

struct Node{
char* data;
Node *next;
};

struct Node *head = NULL;
int length = 0;

void addNode(char* data){
Node* newnode = (struct Node*) malloc(sizeof(struct Node));
newnode->data = data;
newnode->next = NULL;
Node* temp = head;

if(head != NULL){
while(temp->next != NULL)
temp = temp -> next;
temp-> next = newnode;
}
else
head = newnode;
length++; }

void print(){
Node* temp = head;
while(temp != NULL){
cout << "{" << temp->data << "}";
temp = temp->next;
if(temp!=NULL)cout<<",";
}
}

int main(){
static char* line_input = readline("> ");
char* tok = strtok(line_input, " ");
while(tok != NULL){
//cout<<tok<<endl;
char temp[100];
if(tok[0]=='"')
{
strcpy(temp,&tok[1]);
while(tok!=NULL)
{
tok = strtok(NULL, " ");
strcat(temp," ");
  
int l=strlen(tok);
if(tok[l-1]=='"')
{
char d[100];
int k;
for(k=0;k<l-1;k++)
d[k]=tok[k];
d[k]='\0';
strcat(temp,d);
break;
}
else
{
strcat(temp,tok);
}
}
addNode(temp);
}
else
addNode(tok);
tok = strtok(NULL, " ");
}
cout << "[";
print();
cout << "]";
}

Answer 1

Solution :

#include <stdio.h>
#include <cstring>
#include <iostream>
#include <string>
#include <ctype.h>
#include <malloc.h>
#include <readline/readline.h>
#include <readline/history.h>

using namespace std;

struct Node{
   char* data;
   struct Node *next;
};

struct Node *head = NULL;
static int length = 0;

void print();

int addNode(char* data){

   Node* newnode = (struct Node*) malloc(sizeof(struct Node));
   newnode->data = data;
   newnode->next = NULL;
   Node* temp = head;

   if(head != NULL) {
       while(temp->next!= NULL){
           temp = temp -> next;
       }
       temp -> next = newnode;
   }
   else
       head = newnode;
   length++;
return 0;
}

void print(){
   Node* temp = head;
   while(temp != NULL){
       cout << "{" << temp->data << "}";
       temp = temp->next;
       if(temp!=NULL)
           cout<<",";
   }
}

int main(){
   static char* line_input = readline("> ");
   char* tok = strtok(line_input, " ");
   int i=1;
   while(tok != NULL){
       cout<<" <<----------["<<i++<<"]--------->>"<<endl;
       char temp[100];
       if(tok[0]=='"')
       {
           strcpy(temp,&tok[1]);
           print();
           printf(" If part..{%s} ", tok);
           while(tok!=NULL)
           {
               print();
               printf("-Inside while ");
               tok = strtok(NULL, " ");
               strcat(temp," ");

               int l=strlen(tok);
               if(tok[l-1]=='"')
               {
                   printf("-Inside while's IFF ");
                   char d[100];
                   int k;
                   for(k=0;k<l-1;k++)
                       d[k]=tok[k];
                   d[k]='';
                   strcat(temp,d);
                   break;
               }
               else
               {
                   printf("-Inside while's ELSE ");
                   strcat(temp,tok);
               }
           }
           print();
           printf(" Calling ADDNODE temp = [%s] ", temp);
           addNode(temp);
       }
       else {
           printf(" Else part..adding node [%s] ", tok);
           addNode(tok);
       }
       tok = strtok(NULL, " ");
   }
   cout << "[";
   print();
   cout << "]"<<endl;
}

Output:

           

From the above output it is clear that the Second nodes data changes while the process in still executing in the strtok. So the problem is with the strtok and remaining functions are working as expected.