TurnFileWithNumberToList

test

     123 456   789
321   65 98  7
1
1 2 3 4
111111
 111111    222222 333333   

TurnToList.cpp

#include <string>
#include <fstream>
#include <iostream>
using namespace std;

struct ListNode {
    int val;
    ListNode *next;
    ListNode(int _val) {
        val = _val;
        next = NULL;
    }
};

/*
    the file is of lines of numbers, seperated by spaces. Please turn them into linked lists.
    123 456
*/
void readFile(string fileName, ListNode** list, int lineLimit) {
    ifstream ifstrm(fileName);
    if(!ifstrm) {
        exit(1);
    }
    int i = 0;
    string line;
    while (getline(ifstrm, line) && i < lineLimit) {
        // parse this line
        ListNode* dummy = new ListNode(0);
        ListNode *last = dummy;
        int idx = 0;
        while (idx < line.length()) {
            // skip spaces
            while (idx < line.length() && line[idx] == ' ') {
                idx++;
            }
            if (idx == line.length()) break;
            int num = 0;
            while (idx < line.length() && line[idx] != ' ') {
                num = num * 10 + line[idx] - '0';
                idx++;
            }
            ListNode* node = new ListNode(num);
            last->next = node;
            last = node;
        }
        last->next = NULL;
        list[i] = dummy->next;
        delete dummy;
        i++;
    }
    ifstrm.close();
}

int main() {
    const int LINE_COUNT = 100;
    ListNode* list[LINE_COUNT];
    memset(list, 0, sizeof(list));
    readFile("d:\\test.txt", list, LINE_COUNT);
    for (int i = 0; i < LINE_COUNT; i++) {
        ListNode* current = list[i];
        if (current == NULL) break;
        while (current != NULL) {
            cout << current->val << "->";
            current = current->next;
        }
        cout << "NULL" << endl;
    }
    system("pause");
}

TurnToList2.cpp

#include <iostream>
#include <sstream>
using namespace std;

struct LinkNode
{
    int val;
    LinkNode* next;
    LinkNode(int n) : val(n), next(NULL) {}
};

struct HeadNode {
    LinkNode *nextNode;
    HeadNode *nextLine;
    HeadNode() : nextNode(NULL), nextLine(NULL) {}
};

HeadNode* buildList() {
    string line;
    HeadNode headDummy;
    HeadNode *prevHead = &headDummy;
    while (getline(cin, line)) {
        HeadNode *head = new HeadNode();
        prevHead->nextLine = head;
        LinkNode dummy(0);
        LinkNode *prev = &dummy;
        int i = 0;
        while (true) {
            while (i < line.size() && line[i] == ' ') {
                i++;
            }
            if (i == line.size()) {
                break;
            }
            int n = 0;
            while (i < line.size() && line[i] != ' ') {
                n = n * 10 + (line[i] - '0');
                i++;
            }
            LinkNode *node = new LinkNode(n);
            prev->next = node;
            prev = node;
        }
        head->nextNode = dummy.next;
        prevHead = head;
    }
    return headDummy.nextLine;
}

void printList(HeadNode* head) {
    HeadNode *lineHead = head;
    while (lineHead != NULL) {
        LinkNode *node = lineHead->nextNode;
        while (node != NULL) {
            cout << node->val << ",";
            node = node->next;
        }
        cout << endl;
        lineHead = lineHead->nextLine;
    }
}

int main() {
    HeadNode* head = buildList();
    printList(head);
    return 0;
}