MTRX1702 Assignment 1 Solution

ass1.c

/* 
 * MTRX1702 Assignment 1
 * Peter Morton, 2012
 */

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

#define PI 3.14159265358979323846
#define BUF_SIZE 128

typedef enum
{
   ERR = 1,
   DEG = 2,
   RAD = 4,
   SIN = 8,
   COS = 16,
   TAN = 32
} cmd_flags;

void usage(void);
int run_string(char* buf);
unsigned int cmd_to_flags(char *cmd);
void display_table(unsigned int flags, float start, float final, int n_int);
void print_flags(cmd_flags flags);


int main(int argc, char* argv[])
{
    char buf[BUF_SIZE];

    printf("TRIG: the trigonometric calculator\n");

    if(argc > 1)
    {
        int i;
        buf[0] = '\0';
        for(i = 1; i < argc; i++)
        {
            strcat(buf, argv[i]);
            strcat(buf, " ");
        }
        run_string(buf);
        return 0;
    }

    do
    {
        printf("\nPlease input request (h-help, q-quit): ");
        fgets(buf, BUF_SIZE, stdin);
    } while(run_string(buf));

    return 0;
}

void usage(void)
{
    printf("The input format is a single line of letters and numbers comprising\n"
            "the following fields: \n\n"
            "\t<types> <start-value> <final-value> <intermediate-rows>\n\n"
            "These fields must be input in the order shown above, where <types>\n"
            "is a set of letters, and the others are single numbers defining\n"
            "the range of computation. The <types> field consists of zero or more\n"
            "of the letters from the set <stcdr>, which indicate respectively,\n\n"
            "\t(1) The desired trig functions: sin, tan, cos.\n"
            "\t(2) Whether to use degrees or radians for input parameters.\n\n"
            "Example input: scr 0 2.3 3\n");
}


/* Run the command, return TRUE if should continue */
int run_string(char* buf)
{
    char cmd[BUF_SIZE];
    char rem[BUF_SIZE]; /* Remaining (non-parsed) input */
    float start, final;
    int n_int;
    unsigned int flags = 0;

    /* Scan for input in decreasing order of likeliness to fail */
    if(sscanf(buf, "%s %f %f %d%s", cmd, &start, &final, &n_int, rem) == 4)
    {
        if(n_int < 0)
            flags |= ERR;
        else
            flags = cmd_to_flags(cmd);
    }
    else if(sscanf(buf, "%f %f %d%s", &start, &final, &n_int, rem) == 3)
    {
        if(n_int < 0)
            flags |= ERR;
        else
            flags = cmd_to_flags("");
    }
    else if(sscanf(buf, "%s %s", cmd, rem) == 1)
    {
        if(strcmp(cmd, "q") == 0)
        {
            return 0;
        }
        else if(strcmp(cmd, "h") == 0)
        {
            usage();    
            return 1;
        }
        flags |= ERR;
    }
    else
    {
        flags |= ERR;
    }

    /*print_flags(flags);*/

    if(flags & ERR)
    {
        printf("Error: Illegal input!\n");
    }
    else
    {
        display_table(flags, start, final, n_int);
    }

    return 1;
}

/* Convert command string into flags, set ERR flag if problem */
unsigned int cmd_to_flags(char *cmd)
{
    unsigned int flags = 0;
    char *s = cmd;

    for(; *s != '\0'; s++)
    {
        switch(tolower(*s))
        {
            case 's':
                flags |= SIN;
                break;
            case 'c':
                flags |= COS;
                break;
            case 't':
                flags |= TAN;
                break;
            case 'r':
                flags |= RAD;
                break;
            case 'd':
                flags |= DEG;
                break;
            default:
                flags |= ERR;
        }
    }

    /* Check for case that no output column was requested
     * in which case we default to all */
    if((flags & (SIN | COS | TAN)) == 0)
    {
        flags |= (SIN | COS | TAN);
    }

    /* Check that user didn't specify rad and deg 
     * If specified neither, force DEG by default */
    if((flags & RAD) && (flags & DEG))
    {
        flags |= ERR;
    }
    else if(!(flags & RAD))
    {
        flags |= DEG;
    }

    return flags;
}


void display_table(unsigned int flags, float start, float final, int n_int)
{
    char line[BUF_SIZE];
    char *p;
    int i;
    float val;
    float incr;

    /* Convert limits to radians */
    if(flags & DEG)
    {
        start = start * PI / 180.0f;
        final = final * PI / 180.0f;
    }
    
    /* Print header */
    p = line;
    p += sprintf(p, "Degrees,Radians,");
    if(flags & SIN)
        p += sprintf(p, "Sin,");
    if(flags & COS)
        p += sprintf(p, "Cos,");
    if(flags & TAN)
        p += sprintf(p, "Tan,");
    *(p - 1) = '\0'; /* Remove trailing "," */
    printf("%s\n", line);
    
    incr = (final - start) / (n_int + 1);
    for(i = 0; i < n_int + 2; i++)
    {
        val = start + incr * i;
        p = line;
        
        p += sprintf(p, "%0.3f,%0.3f,", val * 180.0 / PI, val);
        if(flags & SIN)
            p += sprintf(p, "%0.3f,", sin(val));
        if(flags & COS)
            p += sprintf(p, "%0.3f,", cos(val));
        if(flags & TAN)
            p += sprintf(p, "%0.3f,", tan(val));
        *(p - 1) = '\0'; /* Remove trailing "," */
        printf("%s\n", line);
    }

}

void print_flags(unsigned int flags)
{
    int i;
    printf("Flags: ");
    for(i = 0; i < 6; i++)
    {
        printf("%d", (flags & (1 << i)) > 0);
    }
    printf("\n");
}