/*
  Name:    ex8-6.c
  Purpose: B1FF filter : practice with one dimensional arrays
  Author:  Bill Slough

  Notes:   Improved solution: introduces functions to the previous solution.
*/

#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>

#define N 80        /* maximum length of input line */

int getline(char a[ ], int size, bool *overflow);
void putline(char a[ ], int n);
void translate(char a[ ], int n);

int main() {
    char line[N];         /* holds one line of input */
    int lineLength;       /* number of characters in the line */
    bool lineOverflow;    /* too many characters input? */

    /* Get a line of input, being careful not to overfill the buffer */
    printf("Enter message: ");
    lineLength = getline(line, N, &lineOverflow);

    /* Terminate execution if there were too many input characters */
    if (lineOverflow) {
        printf("Error in input: buffer overflow.\n");
        return 1;
    }

    /* translate and output the coded message */
    translate(line, lineLength);
    printf("In B1FF speak: ");
    putline(line, lineLength);
    printf("!!!!!!!!!!\n");
    
    return 0;
}


/* Read a line of characters into the array a, which has capacity = size  */
int getline(char a[ ], int size, bool *overflow) {
    int i;
    char ch;
    i = 0;
    while (i < size && (ch = getchar()) != '\n') {
        a[i++] = ch;
    }
    *overflow =  (i == size) && (getchar() != '\n');
    return i;
}

/* Output the n characters stored in a given array */
void putline(char a[ ], int n) {
    int i;
    for (i = 0; i < n; i++)
        printf("%c", a[i]);
}

/* Replace the n characters stored in a given array, using the B1FF rules */
void translate(char a[ ], int n) {
    char ch;
    int i;
    for (i = 0; i < n; i++) {
        ch = toupper(a[i]);
        switch(ch) {
        case 'A': ch = '4'; break;
        case 'B': ch = '8'; break;
        case 'E': ch = '3'; break;
        case 'I': ch = '1'; break;
        case 'O': ch = '0'; break;
        case 'S': ch = '5'; break;
        }
        a[i] = ch;
    }
}