Read from file and use read parts to call functions

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Read from file and use read parts to call functions

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#1 by (0 votes)

1

I have a file that contains calls to functions in my code. Some examples of functions are criar(), inserir(elemento, conjunto), listar(conjunto) where arguments are integers passed to the function. These functions should be called through arquivo.txt which will contain, for example:

criar() inserir(1,0) listar(0)

To read the file, I used the following function:

void leArquivo(){
FILE *arq;

    if((arq = fopen("arquivo.txt", "r")) == NULL)
            printf("Erro ao abrir o arquivo.\n");

    char buffer[100];
    char *p;

    while (fscanf (arq, "%s\n", buffer) != EOF) {
            p = buffer;
            printf("%s\n", p);    
    }    
    fclose (arq);
}

However, this only princes the "name" of the function itself, and does not call it. For example, if in the file the function is criar() , it criar() and not the return of the create function. I found that since printf("%d", criar()); returns the value of the function, printf("%d\n", p); would return the same, but not.

I thought of using the strcmp() function to be able to compare if the names are equal and then call the function, and I succeeded in the functions without arguments, but I do not know how to do for functions of type inserir(elemento, conjunto) , where it is not possible to "predict" the arguments. Any suggestions on how to call these functions from the file reading?

c arquivo

asked by anonymous 04.11.2015 / 18:13

1 answer

VBS Script with error java.lang.NoClassDefFoundError: gnu / io / SerialPortEventListener communication with arduino

score 0 · Answer 1

See if the function below is for your needs:

This code snippet will read the text file and look for the function in an already defined structure and execute the command if it exists.

#include <stdio.h>
#include <stdlib.h>
#include <termios.h>

#include <readline/readline.h>
#include <readline/history.h>

typedef void cmd_function_t(char *);

//estrutura dos comandos
typedef struct {
    char *name;
    cmd_function_t *func;
} command_t;

static void execute_command(char *line);
static command_t *find_command(char *name);

//comandos para rodar
static void comando1(char *arg);
static void comando2(char *arg);
static void comando3(char *arg);
static void comando4(char *arg);

command_t commands[] = {
        { "comando1", comando1 },
        { "comando2", comando2 },
        { "comando3", comando3 },
        { "comando4", comando4 },
};

static command_t *find_command(char *name) {
    register int i;
    size_t namelen;

    if ((name == NULL) || (*name == '#include <stdio.h>
#include <stdlib.h>
#include <termios.h>

#include <readline/readline.h>
#include <readline/history.h>

typedef void cmd_function_t(char *);

//estrutura dos comandos
typedef struct {
    char *name;
    cmd_function_t *func;
} command_t;

static void execute_command(char *line);
static command_t *find_command(char *name);

//comandos para rodar
static void comando1(char *arg);
static void comando2(char *arg);
static void comando3(char *arg);
static void comando4(char *arg);

command_t commands[] = {
        { "comando1", comando1 },
        { "comando2", comando2 },
        { "comando3", comando3 },
        { "comando4", comando4 },
};

static command_t *find_command(char *name) {
    register int i;
    size_t namelen;

    if ((name == NULL) || (*name == '%pre%'))
        return ((command_t *) NULL);

    namelen = strlen(name);
    for (i = 0; commands[i].name; i++) {
        if (strncmp(name, commands[i].name, namelen - 1) == 0) {
            /* make sure the match is unique */
            if ((commands[i + 1].name)
                    && (strncmp(name, commands[i + 1].name, namelen) == 0))
                return ((command_t *) NULL);
            else
                return (&commands[i]);
        }
    }

    return ((command_t *) NULL);
}

//função que pega o texto encontrado e executa
static void execute_command(char *line) {

    register int i;
    command_t *command;
    char *word;

    /* Isolate the command word. */
    i = 0;
    while (line[i] && whitespace(line[i]))
        i++;
    word = line + i;

    while (line[i] && !whitespace(line[i]))
        i++;

    if (line[i])
        line[i++] = '%pre%';

    command = find_command(word);

    if (!command) {
        return;
    }

    /* Get argument to command, if any. */
    while (whitespace(line[i]))
        i++;

    word = line + i;

    /* invoke the command function. */
    (*command->func)(word);
}

static void comando1(char *arg) {

    printf("\nExecutando o Comando 1\n");
    fflush(NULL);
}

static void comando2(char *arg) {

    printf("\nExecutando o Comando 2\n");
    fflush(NULL);
}

static void comando3(char *arg) {

    printf("\nExecutando o Comando 3\n");
    fflush(NULL);
}

static void comando4(char *arg) {

    printf("\nExecutando o Comando 4\n");
    fflush(NULL);
}

int main(int argc, char **argv) {

    FILE * fp;
    char * line = NULL;
    size_t len = 0;
    ssize_t read;
    char *cmd;

    fp = fopen("arquivo.txt", "r");
    if (fp == NULL)
        exit(EXIT_FAILURE);

    if ((read = getline(&line, &len, fp)) != -1) {
        if (line == NULL) {
            printf("Sem comando\n");
        }

        cmd = line;

        if (*cmd) {
            execute_command(cmd);
        }

    }

    fclose(fp);
    if (line)
        free(line);
    exit(EXIT_SUCCESS);

}
'))
        return ((command_t *) NULL);

    namelen = strlen(name);
    for (i = 0; commands[i].name; i++) {
        if (strncmp(name, commands[i].name, namelen - 1) == 0) {
            /* make sure the match is unique */
            if ((commands[i + 1].name)
                    && (strncmp(name, commands[i + 1].name, namelen) == 0))
                return ((command_t *) NULL);
            else
                return (&commands[i]);
        }
    }

    return ((command_t *) NULL);
}

//função que pega o texto encontrado e executa
static void execute_command(char *line) {

    register int i;
    command_t *command;
    char *word;

    /* Isolate the command word. */
    i = 0;
    while (line[i] && whitespace(line[i]))
        i++;
    word = line + i;

    while (line[i] && !whitespace(line[i]))
        i++;

    if (line[i])
        line[i++] = '%pre%';

    command = find_command(word);

    if (!command) {
        return;
    }

    /* Get argument to command, if any. */
    while (whitespace(line[i]))
        i++;

    word = line + i;

    /* invoke the command function. */
    (*command->func)(word);
}

static void comando1(char *arg) {

    printf("\nExecutando o Comando 1\n");
    fflush(NULL);
}

static void comando2(char *arg) {

    printf("\nExecutando o Comando 2\n");
    fflush(NULL);
}

static void comando3(char *arg) {

    printf("\nExecutando o Comando 3\n");
    fflush(NULL);
}

static void comando4(char *arg) {

    printf("\nExecutando o Comando 4\n");
    fflush(NULL);
}

int main(int argc, char **argv) {

    FILE * fp;
    char * line = NULL;
    size_t len = 0;
    ssize_t read;
    char *cmd;

    fp = fopen("arquivo.txt", "r");
    if (fp == NULL)
        exit(EXIT_FAILURE);

    if ((read = getline(&line, &len, fp)) != -1) {
        if (line == NULL) {
            printf("Sem comando\n");
        }

        cmd = line;

        if (*cmd) {
            execute_command(cmd);
        }

    }

    fclose(fp);
    if (line)
        free(line);
    exit(EXIT_SUCCESS);

}