CODEWITHSUNDEEP
cfgetsarrays
Jun1987
Jun1987

Reputation: 15

Reading a file line by line and storing it into array do not work

What I want to do here is to read a text file containing phone numbers. For example:

01011112222
01027413565
01022223333

I want to store these phone numbers into an array for later use. Here below is my code:

#include <stdio.h>
#include <stdlib.h>
int main(){
   FILE *fl = NULL;
   char* phoneNums[10];

   int i = 0;
   fl = fopen("phoneNum.txt", "r");

   if(fl != NULL){
      char strTemp[14];

      while( !feof(fl) ){
        phoneNums[i] = fgets(strTemp, sizeof(strTemp), fl); 
        i++;
      }
      fclose(fl);
   }
   else{
      printf("File does not exist");
   }

   return 0;
}

The problem is that whenever fgets is called, it returns the same reference of strTemp.

So every time it goes through the loop, it changes all value to the recent value in phoneNums array.

I tried to declare char strTemp[14] inside the while loop, but it didn't work.

At this point, what could I try to solve this issue?

Thanks.

Upvotes: 0

Views: 68

Answers (2)

Sathish
Sathish

Reputation: 3870

Hope this will help you

#include <stdio.h>
#include<string.h>
#include <stdlib.h>
int main(){
    FILE *fl = NULL;
    char    phoneNums[3][14]; // you didn't allocate memory here. i am using static memory(for 3 phone numbers)
    int i = 0,j;
    fl = fopen("phoneNum.txt", "r");

    if(fl != NULL){
            char strTemp[14];

            while( fgets(strTemp, sizeof(strTemp), fl) ){
                    strcpy(phoneNums[i],strTemp); // you need to string copy function to copy one string to another string
                    i++;
            }
            fclose(fl);
    }
    else{
            printf("File does not exist");
    }
    for(j=0;j<i;j++) // i am printing the array content
            printf("%s\n",phoneNums[j]);

    return 0;
}

Here the dynamic allocation of memory for char *phoneNums[14];

pnoneNums=(char **)malloc(14*n); // where n is the numbers of phone numbers

Upvotes: 0

Chandru
Chandru

Reputation: 1334

Do the below changes to get the exact result.

Change the strTemp variable to pointer variable.

 char *strTemp;

Inside while allocate the dynamic memory for the variable.

 strTemp=malloc(14);
 phoneNums[i]=fgets(strTemp,14,fl);

If you do like this it will create a new memory for each time so the value is stored in the different location. So it can't overwrite in the same location.

Upvotes: 1

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