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

typedef struct Student
{
    char *name;
    int age;
    double gpa;
} Student;


void printStudent( FILE *fp, const Student *s )
{
    int val = fprintf( fp, "Name=%20s, age=%3d, gpa=%4.2lf\n", s->name, s->age, s->gpa );
    printf( "Return code = %d\n" , val );
}

void readStudent( FILE *fp, Student *s )
{
    static char buffer[ 1024 ];

    fscanf( fp, "%1023s %d %lf", buffer, &s->age, &s->gpa );
    s->name = strdup( buffer );
}

void cleanup( Student *s )
{
    free( s->name );
}

int main( )
{
    Student s1;
    Student s2 = { strdup( "Pat" ), 26, 3.6 };
    Student s3;
    Student s4;
    
    FILE *fout;
    FILE *fin;

    printf( "Sizeof struct is %d\n", sizeof( s1 ) );

    s1.age = 40;
    s1.gpa = 4.0;
    s1.name = strdup( "Chris" );

    fout = fopen( "output.txt", "w" );
    printStudent( fout, &s1 );
    printStudent( fout, &s2 );

    fin = fopen( "input.txt", "r" );


    if( fin == NULL || fout == NULL )
    {
        fprintf( stderr, "Error opening files\n" );
        return 1;
    }
    
    printf( "Reading student: " );
    
    readStudent( fin, &s3 );

    
    printf( "Reading student: " );
    readStudent( fin, &s4 );
    
    printStudent( fout, &s3 );
    printStudent( fout, &s4 );

    cleanup( &s1 );
    cleanup( &s2 );
    cleanup( &s3 );
    cleanup( &s4 );
   
    fclose( fin );
    fclose( fout );

    return 0;
}