CODEWITHSUNDEEP
csegmentation-fault
user3180222
user3180222

Reputation: 1

Segmentation Fault when using fopen on argv

I continue to have a segmentation fault when I try and execute the following code...

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

int main(int argc, char *argv[]){
  if (argc < 4){
     fprintf (stderr,"usage message");
     return (1);
  }

  FILE *src = fopen(argv[1],"r"); //file pointer to inputFile
  FILE *outputFile = fopen(argv[2],"w"); //file pointer to outputFile
  int nth = atoi(argv[3]); //nth term value
  printf("nth term is %d",nth);
  int c;
  int currNum;
  int currCount = 1;

  c = fscanf(src, "%d\n",currNum); //read ints line by line
  while( c == 1 ){
    fscanf(src,"%d\n",currNum);
    ++currCount;
    if (currCount % nth == 0){
      fprintf (outputFile, "%d\n", currNum);
    }
  }
}

I'm not sure if I have to somehow convert argv[1] and argv[2] before I can use them as the file names.

Upvotes: 0

Views: 651

Answers (3)

Nagarjuna
Nagarjuna

Reputation: 46

giving input parameters to "fscanf" is wrong. check below one.......

c = fscanf(src, "%d\n",currNum);  // wrong
c = fscanf(src, "%d\n",&currNum); 
fscanf(src,"%d\n",&currNum);

Upvotes: 1

Digital_Reality
Digital_Reality

Reputation: 4758

You can use atoi to convert to int

int nth = atoi( argv[3] );

You also can NULL check file* src and outfile. If you are not giving correct paths then fopen may fail.

Upvotes: 0

unxnut
unxnut

Reputation: 8839

Did you provide a command line argument? You should check that by using an if statement before opening the files. For example, you could add

if ( argc < 4 )
{
    printf ( stderr, "usage message\n" );
    return ( 1 );
}

Also, change that stoi for argv[3] to atoi.

You don't need to add \n for fscanf. Just "%d" will do fine.

Upvotes: 1

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