Re: How to pass this string into a linked list ?

On Nov 7, 7:24 am, "(2b|!2b)==?" <void-s...@ursa-major.com> wrote:


Here is one way to do so:

    #include <stdio.h>
    #include <malloc.h>

    struct params
    {
        double arg;
        params* next;
    };

    struct mst
    {
        int id;
        params* params;
        mst* next;
    };

    void mst_print(FILE* file, mst* head)
    {
        for(;head; head = head->next)
        {
            fprintf(file, "%d", head->id);
            if(head->params)
            {
                char sep = ':';
                for(params* param = head->params; param; param = param-


                {
                    fprintf(file, "%c%f", sep, param->arg);
                    sep = ',';
                }
            }
            fprintf(file, ";");
        }
    }

    mst* mst_destroy(mst* head)
    {
        while(head)
        {
            mst* node = head;
            head = head->next;
            for(params* node_params = node->params; node_params;)
            {
                params* p = node_params;
                node_params = node_params->next;
                free(p);
            }
            free(node);
        }
        return NULL;
    }

    mst* mst_parse(char const** input)
    {
        mst *head = NULL, **tail = &head;
        while(*input)
        {
            // parse id
            int id, eaten = 0;
            sscanf(*input, "%d%n", &id, &eaten);
            if(!eaten)
                return head;
            *input += eaten;
            // allocate the next mst node and initialise it
            mst* next = (mst*)malloc(sizeof(mst));
            if(!next)
                return mst_destroy(head);
            next->id = id;
            next->params = NULL;
            next->next = NULL;
            // append the node to the list
            *tail = next;
            tail = &next->next;
            // parse params
            if(':' == **input)
            {
                params** tail_params = &next->params;
                ++*input;
                for(;;)
                {
                    double arg;
                    eaten = 0;
                    sscanf(*input, "%lf%n", &arg, &eaten);
                    if(!eaten)
                        return head;
                    *input += eaten;
                    // allocate the next params node and initialise it
                    params* next_params =
(params*)malloc(sizeof(params));
                    if(!next_params)
                        return mst_destroy(head);
                    next_params->arg = arg;
                    next_params->next = NULL;
                    // append to the params list
                    *tail_params = next_params;
                    tail_params = &next_params->next;
                    // see if there are more params
                    if(',' != **input)
                        break;
                    ++*input;
                }
            }
            // see if there are more ids
            if(';' != **input)
                break;
            ++*input;
        }
        return head;
    }

    char const* inputs[] = {
        ""
        , "1"
        , "1:1.0"
        , "1:1.0,2.0"
        , "1:1.0,2.0;2:11.0,22.0;"
        , "1:1.0,2.0;2:11.0,22.0;qwerty"
        , NULL
    };

    int main()
    {
        for(char const** i = inputs; *i; ++i)
        {
            char const* input = *i;
            printf("parsing '%s': ", input);
            mst* head = mst_parse(&input);
            if(*input)
                printf("<choked at postion %d> ", (int)(input - *i));
            mst_print(stdout, head);
            mst_destroy(head);
            printf("\n");
        }
    }

Output:
    parsing '':
    parsing '1': 1;
    parsing '1:1.0': 1:1.000000;
    parsing '1:1.0,2.0': 1:1.000000,2.000000;
    parsing '1:1.0,2.0;2:11.0,22.0;':
1:1.000000,2.000000;2:11.000000,22.000000;
    parsing '1:1.0,2.0;2:11.0,22.0;qwerty': <choked at postion 22>
1:1.000000,2.000000;2:11.000000,22.000000;

--
Max