/*
* formatted_io.c
* Stephanie Taylor
*
* Set of functions demonstrating formatted text-IO in C
* 
*/

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

// There are 3 FILE*'s that are included in the library
// stdin: scanf reads from Terminal
// stdout: printf writes to Terminal
// stderr: printf writes to Terminal with emphasis (right away and sometimes with additional formatting)
void test0a() {
//     printf( "Hi, write something: " );
    fprintf( stdout, "Hi, write something: " ); // equivalent to line above
//     fprintf( stdout, "Hi, write something: \n" ); // if \n is there, then this is flushed out before the error message
    fprintf( stderr, "error, though" );
    // without the \n in in the printf to stdout, the message to stderr appears first
}

// We use a format string to indicate what we want to read in.
// The return value indicates how many format patterns were
// matched. In this case, we are expecting up to 1 to be matched (%d)
void test0b() {
    printf( "write something: " );
    int readMe;
    int succ = scanf( "%d", &readMe );
    if (succ) {
        printf( "Successfully read %d\n", readMe );
    }
    else {
        printf( "Failed: success=%d\n", succ );
    }
}

// how tell if end of format
// we can't just put two ints back to back
void test0c() {
    int a, b;
    float c;
    int succ;
//     succ = scanf( "%d%d", &a, &b );
//     printf( "a=%d b=%d succ=%d\n", a, b, succ );
//     printf( "hi: " );
    succ = scanf( "(%d,%d)", &a, &b );
    printf( "a=%d b=%d succ=%d\n", a, b, succ );
}

// test fscanf to see if it automatically
// does the splitting. It does.
// We use the format string as a pattern-matcher
// We look for a string, repeatedly.
void test1a() {
    FILE *fp = fopen( "test.txt", "r" );
    if (fp == NULL)
        return;
    //char word[100]; // strings longer than 100 will cause an error.
    char word[9]; // strings longer than 9 will cause an error.
    while (1) {
        int c = fscanf( fp, "%s", word);
        if (c == EOF) break;
        printf( "%d %s\n", c, word );  
    }
}

// Match more than one pattern.
// We use the format string as a pattern-matcher
// We look for a string followed by a space followed by an integer
// If it matches both the string and num, fscanf returns 2 and puts the string in word
// and the integer in my_int.
// If it matches only one, it returns 1 and puts what it found in the appropriate variable.
void test1b() {
    FILE *fp = fopen( "test.txt", "r" );
    if (fp == NULL)
        return;
    char word[100];
    long int my_int = 9;
    while (1) {
        int c = fscanf( fp, "%s %ld", word, &my_int );
        if (c == EOF) break;
        printf( "%d %s %ld\n", c, word, my_int );  
    }
}

// printf is the same as fprintf to stdout, which is a FILE* that
// is special.
void test2() {
    fprintf( stdout, "Hello, world\n" );
}

int main(int argc, char* argv[]) {
//     test0c();
//     test1a();
    test1b();
//     test2();
    return 0;
}