Genetic code conversion routine implemented in constant time using a lookup table. It supports both DNA and mRNA sequences.

genetic_code.c

/*
 * Copyright (C) 2014 Carlos Jenkins <[email protected]>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * Genetic code conversion routine implemented in constant time using a lookup
 * table. It supports both DNA and mRNA sequences.
 * Compile me with:
 *     gcc -o genetic_code genetic_code.c
 */

#include <stdio.h>

static const char GENETIC_CODE[4][4][4] = {
/*                 U                     C                     A                     G          */
/*         _________________     _________________     _________________     _________________  */
/*           U   C   A   G         U   C   A   G         U   C   A   G         U   C   A   G    */
/* U */ {  {'F','F','L','L'}  ,  {'S','S','S','S'}  ,  {'Y','Y','*','*'}  ,  {'C','C','*','W'}  },
/* C */ {  {'L','L','L','L'}  ,  {'P','P','P','P'}  ,  {'H','H','Q','Q'}  ,  {'R','R','R','R'}  },
/* A */ {  {'I','I','I','M'}  ,  {'T','T','T','T'}  ,  {'N','N','K','K'}  ,  {'S','S','R','R'}  },
/* G */ {  {'V','V','V','V'}  ,  {'A','A','A','A'}  ,  {'D','D','E','E'}  ,  {'G','G','G','G'}  }
};

unsigned int base_index(char which_one)
{
    int result = 0; // Default, U and T

    switch(which_one) {
        case 'C':
            result = 1;
            break;
        case 'A':
            result = 2;
            break;
        case 'G':
            result = 3;
            break;
    }

    return result;
}

int main(int argc, char **argv)
{

    char code[] = "AAU";

    char amino = GENETIC_CODE[base_index(code[0])][base_index(code[1])][base_index(code[2])];
    printf("Aminoacid for AAU is: %c \n", amino);

    return(0);
}