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

// You need to help C by separating floats...
void format_carefully() {
    FILE * fp;
    fp = fopen("tmp", "w");
    fprintf( fp, "%f%f", 1.0,2.0 );
    fclose(fp);
    fp = fopen("tmp", "r");
    float a, b;
    fscanf( fp, "%f%f", &a, &b );
    printf( "a = %f, b = %f\n", a, b );  
    fclose(fp);  
}

void mix_text_binary( char *filename ) {
    FILE * fp;
    fp = fopen(filename, "w");
    if (fp == NULL) {
        printf( "Something went wrong attempting to open %s\n", filename );
        return;
    }
    double a = 1.2345e-3/7.0;
    
    fprintf( fp, "%0.20lf,", a );
    fwrite( &a, sizeof(double), 1, fp );
    fclose( fp );
    
    fp = fopen( filename, "r" );
    if (fp == NULL) {
        printf( "Something went wrong attempting to open %s\n", filename );
        return;
    }
    double b;
    fscanf( fp, "%lf,", &b );
    double c;
    fread( &c, sizeof(double), 1, fp );
    printf( "read in %0.8f and %0.8f\n", b, c );
    printf( "difference is %e\n", b-c );
    fclose(fp);
}

void test_endian() {
    unsigned int a = 1;
    FILE *fp = fopen( "short", "w" );
    fwrite( &a, sizeof(unsigned int), 1, fp );
    fclose(fp);
}

typedef struct C3 {
    char a;
    char b;
    char c;
} C3;

void test_structs() {
    C3 *arr = malloc( sizeof(C3) * 3 );
    printf( "sizeof C3 %d\n", sizeof(C3) );
    for (int i = 0; i < 3; i++) {
        arr[i].a = 'a';
        arr[i].b = 'b';
        arr[i].c = 'c';
    }    
    FILE *fp = fopen( "structs", "w" );
    fwrite( arr, sizeof(C3), 3, fp );
    fclose(fp);
    fp = fopen( "structs", "r" );
    fread( arr, sizeof(C3)*3, 1, fp );
    fclose( fp );
    for (int i =0; i < 3; i++)
       printf( "%c %c %c\n", arr[i].a, arr[i].b, arr[i].c );
}

int main(int argc, char* argv[]) {
    //format_carefully();
    //test_endian();
    test_structs();   
    //if (argc  <= 1) {
    //    printf( "Usage: ./compare_io <filename>\n" );
    //    printf( "   where <filename> is the name of a file that will be written to and then read from\n" );
    //    return 1;
    //}
    //mix_text_binary( argv[1] );
    
    return 0;
}