resistormaid/resistormaid.c

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

int16_t value = 0;
int16_t sixDigit = 0;
float tolerance = 20;
float multiplier = 0;
int8_t hasThirdValueBand = 0;
int8_t k,m,g = 0;

int colorValues(char *colorInput) {
    if(!strcmp(colorInput, "black"))          return 0;
    else if(!strcmp(colorInput, "brown"))     return 1;
    else if(!strcmp(colorInput, "red"))       return 2;
    else if(!strcmp(colorInput, "orange"))    return 3;
    else if(!strcmp(colorInput, "yellow"))    return 4;
    else if(!strcmp(colorInput, "green"))     return 5;
    else if(!strcmp(colorInput, "blue"))      return 6;
    else if(!strcmp(colorInput, "violet"))    return 7;
    else if(!strcmp(colorInput, "purple"))    return 7;
    else if(!strcmp(colorInput, "gray"))      return 8;
    else if(!strcmp(colorInput, "grey"))      return 8;
    else if(!strcmp(colorInput, "white"))     return 9;
    else if(!strcmp(colorInput, "gold"))      return -1;
    else if(!strcmp(colorInput, "golden"))    return -1;
    else if(!strcmp(colorInput, "silver"))    return -2;
    else return -3;
}

float toleranceValues(char *toleranceInput) {
    if(!strcmp(toleranceInput, "brown"))          return 1;
    else if(!strcmp(toleranceInput, "red"))       return 2;
    else if(!strcmp(toleranceInput, "orange"))    return 3;
    else if(!strcmp(toleranceInput, "yellow"))    return 4;
    else if(!strcmp(toleranceInput, "green"))     return 0.5;
    else if(!strcmp(toleranceInput, "blue"))      return 0.25;
    else if(!strcmp(toleranceInput, "violet"))    return 0.1;
    else if(!strcmp(toleranceInput, "purple"))    return 0.1;
    else if(!strcmp(toleranceInput, "gray"))      return 0.05;
    else if(!strcmp(toleranceInput, "grey"))      return 0.05;
    else if(!strcmp(toleranceInput, "gold"))      return 5;
    else if(!strcmp(toleranceInput, "golden"))    return 5;
    else if(!strcmp(toleranceInput, "silver"))    return 10;
    else return -1;
}

int main(int argc, char **argv) { 
    int8_t numargs = argc - 1; // this is more practical than doing (argc - 1) every call
    if(numargs > 6) {
        printf("Too many arguments! Exiting now.\n");
        goto exit;
    } else if(numargs == 0) {
        printf("Usage: resistormaid first second [third] multiplier [tolerance] [temp_coefficient]\n");
        printf("Valid arguments: black, brown, red, orange, yellow, green, blue, violet, purple, gray, grey, white, gold, golden, silver\n");
        goto exit;
    } else if(numargs < 3) {
        printf("Too few arguments! Exiting now.\n");
        goto exit;
    }

    for(int i = 1; i <= numargs; i++) {
        for(int j = 0; argv[i][j]; j++) argv[i][j] = tolower(argv[i][j]);
    }

    int8_t firstDigit = colorValues(argv[1]);
    int8_t secondDigit = colorValues(argv[2]);
    if(firstDigit < 0) {
        printf("Invalid first argument! Exiting now.\n");
        goto exit;
    } else if(secondDigit < 0) {
        printf("Invalid second argument! Exiting now.\n");
        goto exit;
    }
    value = firstDigit * 10 + secondDigit; // handles argv[1] and argv[2]

    if(numargs > 4) {
        hasThirdValueBand = 1;
        int8_t thirdDigit = colorValues(argv[3]); // handles argv[3]
        if(thirdDigit < -2) {
            printf("Invalid third argument! Exiting now.\n");
            goto exit;
        }
        value = value * 10 + thirdDigit;
    }

    multiplier = colorValues(argv[3 + hasThirdValueBand]); // handles argv[3] and argv[4]
    if(multiplier < -2) {
        if(hasThirdValueBand) printf("Invalid fourth argument! Exiting now.\n");
        else printf("Invalid third argument! Exiting now.\n");
        goto exit;
        }

    if(numargs > 3) { // handles argv[4] and argv[5]
        tolerance = toleranceValues(argv[4 + hasThirdValueBand]);
        if(tolerance == -1) {
            if(hasThirdValueBand) printf("Invalid fifth argument! Exiting now.\n");
            else printf("Invalid fourth argument! Exiting now.\n");
            goto exit;
        }
    }

    multiplier = pow(10.0, multiplier);
    float output = value * multiplier;

    if(output >= 1000.0) {
        k = 1;
        output = output / 1000;
    }
    if(output >= 1000.0) {
        m = 1;
        output = output / 1000;
    }
    if(output >= 1000.0) {
        g = 1;
        output = output / 1000;
    }

    if(numargs > 5) { // handles argv[6]
        if(!strcmp(argv[6], "black"))       sixDigit = 250;
        else if(!strcmp(argv[6], "brown"))  sixDigit = 100;
        else if(!strcmp(argv[6], "red"))    sixDigit = 50;
        else if(!strcmp(argv[6], "orange")) sixDigit = 15;
        else if(!strcmp(argv[6], "yellow")) sixDigit = 25;
        else if(!strcmp(argv[6], "green"))  sixDigit = 20;
        else if(!strcmp(argv[6], "blue"))   sixDigit = 10;
        else if(!strcmp(argv[6], "violet")) sixDigit = 5;
        else if(!strcmp(argv[6], "purple")) sixDigit = 5;
        else if(!strcmp(argv[6], "gray"))   sixDigit = 1;
        else if(!strcmp(argv[6], "grey"))   sixDigit = 1;
        else {
            printf("Invalid sixth value! Exiting now.\n");
            goto exit;
        }
    }
    char stringOut[16];  // remove the unnecessary '.' and '0' characters
    sprintf(stringOut, "%.2f", output);
    int8_t counter = strlen(stringOut) - 1;
    int8_t exitTracker = 0;
    while(stringOut[counter] == '0' || stringOut[counter] == '.') {
        if(stringOut[counter] == '.') exitTracker = 1; // so we stop after the dot
        stringOut[counter] = '\0';
        counter--;
        if(exitTracker) break;
    }

    printf("%s", stringOut);
    if(g) printf("G");
    else if(m) printf("M");
    else if(k) printf("K");

    printf(" Ohm +-%g%%", tolerance);
    if(sixDigit != 0) printf(" %ippm", sixDigit);
    printf("\n");
    exit:
    return 0;
}