Hello all,

I keep getting a segmentation fault when I run this compiled program.

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


/* write a struct to the file */
void WritePersonFixedLength(struct person * input, FILE * target)
{
    
        //use fprintf to write input->firstname '%-20s'
        fprintf(target, "%-20s", input->firstname);
        
	//use fprintf to write input->middlename '%-20s'
        fprintf(target, "%-20s", input->middlename);
	//use fprintf to write input->lastname '%-20s'
        fprintf(target, "%-20s", input->lastname);
	//use fprintf to write input->age '%8d'
        fprintf(target, "%8d", input->age);

	/* add a newline to the file so that it is a whole lot more readable, 
	 we need to remember to skip this when we read it out			*/
        fprintf(target, "\n");
}


int main()
{


struct person person1,person2,person3,person4,person5;
/* create a FILE pointer myfile */
FILE * myfile;

strcpy(person1.firstname,"Bartholomew");
strcpy(person1.middlename,"");
strcpy(person1.lastname,"Simpson");
person1.age=10;

strcpy(person2.firstname,"Homer");
strcpy(person2.middlename,"Jay");
strcpy(person2.lastname,"Simpson");
person2.age=36;

strcpy(person3.firstname,"Lisa");
strcpy(person3.middlename,"");
strcpy(person3.lastname,"Simpson");
person3.age=8;

strcpy(person4.firstname,"Marjorie");
strcpy(person4.middlename,"");
strcpy(person4.lastname,"Simpson");
person4.age=34;

strcpy(person5.firstname,"Margaret");
strcpy(person5.middlename,"");
strcpy(person5.lastname,"Simpson");
person5.age=1;


/* use fopen to open the file data.dat in 
   WRITE mode and set the pointer myfile */
myfile = fopen("data.txt","w");
/* if the fopen operation was not successful print a message saying 
   the file couldn't be opened then quit the program 'exit(1);' */ 
if (myfile = NULL)
{
    printf("the file couldn't be opened");
    exit(1);
}


printf("\n\nWrite the 5 structs to file\n\n");
WritePersonFixedLength(&person1, myfile);
WritePersonFixedLength(&person2, myfile);
WritePersonFixedLength(&person3, myfile);
WritePersonFixedLength(&person4, myfile);
WritePersonFixedLength(&person5, myfile);


/* use close to close the File pointer myfile */
fclose(myfile);
}

this is the header file "person.h" that goes with the above program

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

struct person
{
char	firstname[20];
char	middlename[20];
char	lastname[20];
int	age;
};

void PrintPerson( struct  person input)
{
printf("First Name: %s\n", input.firstname);
printf("Middle Name: %s\n",input.middlename);
printf("Last Name: %s\n", input.lastname);
printf("Age: %d\n\n",input.age);
}

anyone have any ideas as to why I keep getting a segmentation fault?

Line 68, your setting myfile to NULL. It should be myfile == NULL

I'm surprised your compiler didn't complain about that line. I corrected it and the program works now.

Edited 6 Years Ago by gerard4143: n/a

Line 68, your setting myfile to NULL. It should be myfile == NULL

I'm surprised your compiler didn't complain about that line. I corrected it and it works.

Just did the same thing. I figured it would give me something for that too. Oh well, thank you very much!

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