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Adding characters to an array as integers in C


I am trying to add integers to an array in C. However I'm reading characters in from a file, so I have to convert them to integers first. For some reason my program wont even start up now before it stops working. I think it is a conversion problem but I am new to C.

new edit code:

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

int main (void)
{
    FILE* fp;
    const char filename[] = "test.txt";
    char ch;
    int num[1000];
    int j = 0;
    char temp;

    fp = fopen(filename, "r");
    if( fp == NULL )
    {
        printf( "Cannot open file: %s\n", filename);
        exit(8);
    }

    while(!feof(fp))
    {
        temp = fgetc(fp);
        num[j] = temp - '0';
        j++;
    }
    printf("First in the array is: %d,  last is; %d", num[0], num[999]);


    fclose(fp);

    return EXIT_SUCCESS;
}

test.txt

731671765313306249192251196744265747423553491949349698352031277450632623957831801698480186947885184385861560789112949495459501737958331952853208805511
125406987471585238630507156932909632952274430435576689664895044524452316173185640309871112172238311362229893423380308135336276614282806444486645238749
303589072962904915604407723907138105158593079608667017242712188399879790879227492190169972088809377665727333001053367881220235421809751254540594752243
525849077116705560136048395864467063244157221553975369781797784617406495514929086256932197846862248283972241375657056057490261407972968652414535100474
821663704844031998900088952434506585412275886668811642717147992444292823086346567481391912316282458617866458359124566529476545682848912883142607690042
242190226710556263211111093705442175069416589604080719840385096245544436298123098787992724428490918884580156166097919133875499200524063689912560717606
0588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450

Someone to point me in the right direction would be great.


Solution

  • I am rephrasing my entire answer after you added the contents of test.txt.

    Instead of

    while(!feof(fp))
    {
        temp = fgetc(fp);
        num[j] = temp - '0';
        j++;
    }
    

    Change to

    while(!feof(fp)&& (j<1000))
    {
        temp = fgetc(fp);
        if ( temp != EOF && ( temp>='0' && temp<='9') ) // To filter out non-numbers and also the last EOF
           num[j++] = temp - '0';
    
    }
    

    And instead of

    printf("First in the array is: %d,  last is; %d", num[0], num[999]);
    

    Change to

    printf("First in the array is: %d,  last is; %d", num[0], num[j-1]); // j-1 so that it works even when there are less than 1000 numbers and to keep it generic
    

    And your done!