Read A File From A Specific Line

The object of my assignment is to read data from a file, capitalize the first letter of all the names within the file and rewrite the file. Simple enough right?

Just one small problem. The file we have to use has a title. It looks like this:

ID FIRSTNAME LASTNAME
10 john doe
20 mary jane

30 jim smith
This ID FIRSTNAME LASTNAME bit here messes up my file reading. I need to know how to read a file from whatever line I want. My code is as follows:

Code:

#include <stdio.h>
struct employee
{
	char firstname[40];
	char lastname[40];
	int id;
};
typedef struct employee Employee;

Employee e[3];

void PrintEmployeeRecord();
void SaveEmployeeRecord();
//void Capitalize(const Employee e[]);

int main ()
{
	int i=0, j =0, r=0, c=0;
	Employee e[3];
	
	
	FILE *file;	
	
	file = fopen("employee.dat", "r");// open file
	
	if(file ==NULL){
		printf("Cannot create file");//initiate check
		return;
	}
	
	for (i=0; i<3; i++)
	{
		fscanf(file,"%d", &e[i].id);
		fscanf(file,"%s", e[i].firstname);
		fscanf(file,"%s", e[i].lastname);
	}
	
	
	fclose(file); //close file
	
	PrintEmployeeRecord();
	
	//Capitalize(e);
	
	PrintEmployeeRecord();
	
	SaveEmployeeRecord(e);
}
//END MAIN FUNCTION


//purpose: Save employee record to file
//input: array of 3 employee data
//output: file with 3 employee data
void SaveEmployeeRecord(const Employee e[])
{
	int i;
	FILE *file;	
	
	file = fopen("employee.dat", "w"); // open file
	
	if(file ==NULL){
		printf("Cannot create file");//initiate check
		return;
	}
	
	fprintf(file, "ID FIRSTNAME LASTNAME\n");  // print starter data
	
	for (i=0; i<3; i++)
	{
		fprintf(file, "%d %s %s \n", e[i].id, e[i].firstname, e[i].lastname); //print file data
	}
	printf("\n Written to file! \n");
	
	fclose(file);// close file
}

//purpose: Print Employee data
//input: array of 3 employee data
//output: 3 employee data printed to screen
void PrintEmployeeRecord()
{
	int i;
	for (i=0; i<3; i++);
	{
		printf("%d %s %s \n", e[i].id, e[i].firstname, e[i].lastname);
	}
}

Since I haven't been able to properly read the file, I therefore haven't written my capitalize function (hence why it's commented out) but I suspect that I'll simply be using toupper(); in order to do this. (if this isn't the right way to go, please tell me)


Can someone help me?

Use fgets to read the first line of the file, don't process it, then go into your read loop.

You could do this a few ways. Probably the easiest is to just read every line with fgets, then check the first character that you've got stored and see if it is 'I'. If so, ignore what you have read, and read the next line. If it's a number, then use something like sscanf (similar to how you are using fscanf) to parse what you've read.


Quzah.

Originally Posted by anduril462

Use fgets to read the first line of the file, don't process it, then go into your read loop.

I tried what you said and I had issues. I added the fgets before the loop and got the error "incompatible type for argument 1 of fgets"

Code:

	if(file ==NULL){
		printf("Cannot create file");//initiate check
		return;
	}
	
	fgets(e[i], sizeof e[i], stdin);
	for (i=0; i<3; i++)
	{
		fscanf(file,"%d", &e[i].id);
		fscanf(file,"%s", e[i].firstname);
		fscanf(file,"%s", e[i].lastname);
	}

Look at the definition of fgets:

Originally Posted by man page

char *fgets(char *s, int size, FILE *stream);

You need to pass it a char *, not an Employee object. You also don't want to read from stdin. You're reading that from the same file as the rest of your data:

Code:

char buf[256];

fgets(buf, sizeof(buf), file);

Originally Posted by anduril462

Look at the definition of fgets:


You need to pass it a char *, not an Employee object. You also don't want to read from stdin. You're reading that from the same file as the rest of your data:

Code:

char buf[256];

fgets(buf, sizeof(buf), file);

This is what I have

Code:

	*fgets(char *e, sizeof(e), file);

Yay, another selfish cross-poster!

Originally Posted by dsured

This is what I have

Code:

	*fgets(char *e, sizeof(e), file);

You can't inline declare e there to be a pointer to a character, and even if you could, you wouldn't have anything allocated for it.

You need a buffer of some kind (an array of characters):

Code:

char mybuf[ SOMESIZEYOUPICK ];

You pass that to it as the first argument, as shown above:

Code:

rval = fgets( mybuf, SOMESIZEYOUPICK, file );

Now typically you want to pay attention to the return value of the function as well.


Quzah.

Code:

  file = fopen("employee.dat", "r");// open file
  if(file ==NULL){
     printf("Cannot create file");//initiate check
     return;
   }

  int i = 0;
  int c = 0;
   do
     {  c = fscanf(file,"%d %s %s", &e[i].id, e[i].firstname, e[i].lastname);
            if (c == 3)  // all three matched the format
              i++ ;
                }
       } while ( c > EOF )  // end of file

   fclose(file); //close file