CODEWITHSUNDEEP
cstringfunction
Tamalero
Tamalero

Reputation: 471

string as a argument in a function in c

I'm making a function for retrieving a integer from a text file, according with its line and field number.

The code is shown below, the main issue is that I'm having problems with the functions arguments.

I'm having an error flag at the return value; it says: that value is undeclare

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

/* define function */
int getlinefieldint(const char FILENAME[], int TARGETLINE, int TARGETFIELD, int LINESIZE);

int main ()
{
    static const char FILENAMEint[] = "resultdata1M";
    int linea=1000;
    int campo=2;
    int tamanolinea=128;
    int value;
    value=getlinefieldint(FILENAMEint,linea,campo,tamanolinea);
    printf("%d",value);

    return 0;
}

/* declare function */
int getlinefieldint(const char FILENAME[], int TARGETLINE, int TARGETFIELD, int LINESIZE)
{
    FILE *ARCHIVO;
    ARCHIVO = fopen ( FILENAME, "r" );       
    int C,QUERY_GENE_NUM;
    unsigned int NEWLINE_COUNT = 0;
    while ( (C=fgetc(ARCHIVO)) != EOF )
    {
        if ( C == '\n' )
        {
        NEWLINE_COUNT++;
        }
    }
    printf("La cantidad de genes a evaluar es: %d\n",QUERY_GENE_NUM);
    rewind(ARCHIVO);

    if (TARGETLINE <= NEWLINE_COUNT)
    {
        int j,value;
        int stoplimitline;
        char LINE[LINESIZE];
        char *BUFFER;
        char *TOKEN_SEPARA;
        char *RETURNPTR;
        BUFFER=(char *)malloc(24 * sizeof(char));
        RETURNPTR=(char *)malloc(24 * sizeof(char));
        while (stoplimitline < TARGETLINE)
        {
            fgets(LINE, sizeof LINE, ARCHIVO);
            puts(LINE);
        }
        TOKEN_SEPARA = strtok(LINE, " ");
        for (j=1;j<=TARGETFIELD;j++)
            {
                if(j!= TARGETFIELD)
                {
                    BUFFER=strcpy(RETURNPTR,TOKEN_SEPARA);
                    puts(BUFFER);
                    TOKEN_SEPARA = strtok(NULL, " ");   /* hacer que brinque el puntero al siguiente patron */
                }
                else
                {
                    value=atoi(BUFFER);
                }
            }


    }

    return value ;
}

Upvotes: 0

Views: 72

Answers (3)

Blue Ice
Blue Ice

Reputation: 7922

value will cease to exist once

if (TARGETLINE <= NEWLINE_COUNT)

goes out of scope, because value's declaration is within the if statement.

The return statement is outside of the if statement, which means that value will be attempted to be returned even though it does not exist.

Upvotes: 3

Ashalynd
Ashalynd

Reputation: 12563

Put the declaration of value outside of if block.

/* declare function */
int getlinefieldint(const char FILENAME[], int TARGETLINE, int TARGETFIELD, int LINESIZE)
{
    FILE *ARCHIVO;
    int value = 0; //or whatever default value it should have

Upvotes: 2

Freyja
Freyja

Reputation: 40804

Your problem lies here:

if (TARGETLINE <= NEWLINE_COUNT)
{
    int j, value;
    // ...
}
return value;

Note that in C (and many other languages), variables only "exist" in the code block they are declared in. So if you declare a variable inside a code block (such as an if, while or for code block), then the variable will simply not exist when the program leaves this block of code.

The simple solution here is then to declare int value before you enter the if block:

int value;
if (TARGETLINE <= NEWLINE_COUNT)
{
    int j;
    // ...
}
return value;

Upvotes: 5

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