Chemical calculator: Difference between revisions

=={{header|C}}==

<lang c>#include <stdio.h>

#include <stdlib.h>

#include <string.h>

typedef char *string;

typedef struct node_t {

string symbol;

double weight;

struct node_t *next;

} node;

node *make_node(string symbol, double weight) {

node *nptr = malloc(sizeof(node));

if (nptr) {

nptr->symbol = symbol;

nptr->weight = weight;

nptr->next = NULL;

return nptr;

}

return NULL;

}

void free_node(node *ptr) {

if (ptr) {

free_node(ptr->next);

ptr->next = NULL;

free(ptr);

}

}

node *insert(string symbol, double weight, node *head) {

node *nptr = make_node(symbol, weight);

nptr->next = head;

return nptr;

}

node *dic;

void init() {

dic = make_node("H", 1.008);

dic = insert("He", 4.002602, dic);

dic = insert("Li", 6.94, dic);

dic = insert("Be", 9.0121831, dic);

dic = insert("B", 10.81, dic);

dic = insert("C", 12.011, dic);

dic = insert("N", 14.007, dic);

dic = insert("O", 15.999, dic);

dic = insert("F", 18.998403163, dic);

dic = insert("Ne", 20.1797, dic);

dic = insert("Na", 22.98976928, dic);

dic = insert("Mg", 24.305, dic);

dic = insert("Al", 26.9815385, dic);

dic = insert("Si", 28.085, dic);

dic = insert("P", 30.973761998, dic);

dic = insert("S", 32.06, dic);

dic = insert("Cl", 35.45, dic);

dic = insert("Ar", 39.948, dic);

dic = insert("K", 39.0983, dic);

dic = insert("Ca", 40.078, dic);

dic = insert("Sc", 44.955908, dic);

dic = insert("Ti", 47.867, dic);

dic = insert("V", 50.9415, dic);

dic = insert("Cr", 51.9961, dic);

dic = insert("Mn", 54.938044, dic);

dic = insert("Fe", 55.845, dic);

dic = insert("Co", 58.933194, dic);

dic = insert("Ni", 58.6934, dic);

dic = insert("Cu", 63.546, dic);

dic = insert("Zn", 65.38, dic);

dic = insert("Ga", 69.723, dic);

dic = insert("Ge", 72.630, dic);

dic = insert("As", 74.921595, dic);

dic = insert("Se", 78.971, dic);

dic = insert("Br", 79.904, dic);

dic = insert("Kr", 83.798, dic);

dic = insert("Rb", 85.4678, dic);

dic = insert("Sr", 87.62, dic);

dic = insert("Y", 88.90584, dic);

dic = insert("Zr", 91.224, dic);

dic = insert("Nb", 92.90637, dic);

dic = insert("Mo", 95.95, dic);

dic = insert("Ru", 101.07, dic);

dic = insert("Rh", 102.90550, dic);

dic = insert("Pd", 106.42, dic);

dic = insert("Ag", 107.8682, dic);

dic = insert("Cd", 112.414, dic);

dic = insert("In", 114.818, dic);

dic = insert("Sn", 118.710, dic);

dic = insert("Sb", 121.760, dic);

dic = insert("Te", 127.60, dic);

dic = insert("I", 126.90447, dic);

dic = insert("Xe", 131.293, dic);

dic = insert("Cs", 132.90545196, dic);

dic = insert("Ba", 137.327, dic);

dic = insert("La", 138.90547, dic);

dic = insert("Ce", 140.116, dic);

dic = insert("Pr", 140.90766, dic);

dic = insert("Nd", 144.242, dic);

dic = insert("Pm", 145, dic);

dic = insert("Sm", 150.36, dic);

dic = insert("Eu", 151.964, dic);

dic = insert("Gd", 157.25, dic);

dic = insert("Tb", 158.92535, dic);

dic = insert("Dy", 162.500, dic);

dic = insert("Ho", 164.93033, dic);

dic = insert("Er", 167.259, dic);

dic = insert("Tm", 168.93422, dic);

dic = insert("Yb", 173.054, dic);

dic = insert("Lu", 174.9668, dic);

dic = insert("Hf", 178.49, dic);

dic = insert("Ta", 180.94788, dic);

dic = insert("W", 183.84, dic);

dic = insert("Re", 186.207, dic);

dic = insert("Os", 190.23, dic);

dic = insert("Ir", 192.217, dic);

dic = insert("Pt", 195.084, dic);

dic = insert("Au", 196.966569, dic);

dic = insert("Hg", 200.592, dic);

dic = insert("Tl", 204.38, dic);

dic = insert("Pb", 207.2, dic);

dic = insert("Bi", 208.98040, dic);

dic = insert("Po", 209, dic);

dic = insert("At", 210, dic);

dic = insert("Rn", 222, dic);

dic = insert("Fr", 223, dic);

dic = insert("Ra", 226, dic);

dic = insert("Ac", 227, dic);

dic = insert("Th", 232.0377, dic);

dic = insert("Pa", 231.03588, dic);

dic = insert("U", 238.02891, dic);

dic = insert("Np", 237, dic);

dic = insert("Pu", 244, dic);

dic = insert("Am", 243, dic);

dic = insert("Cm", 247, dic);

dic = insert("Bk", 247, dic);

dic = insert("Cf", 251, dic);

dic = insert("Es", 252, dic);

dic = insert("Fm", 257, dic);

dic = insert("Uue", 315, dic);

dic = insert("Ubn", 299, dic);

}

double lookup(string symbol) {

for (node *ptr = dic; ptr; ptr = ptr->next) {

if (strcmp(symbol, ptr->symbol) == 0) {

return ptr->weight;

}

}

printf("symbol not found: %s\n", symbol);

return 0.0;

}

double total(double mass, int count) {

if (count > 0) {

return mass * count;

}

return mass;

}

double total_s(string sym, int count) {

double mass = lookup(sym);

return total(mass, count);

}

double evaluate_c(string expr, size_t *pos, double mass) {

int count = 0;

if (expr[*pos] < '0' || '9' < expr[*pos]) {

printf("expected to find a count, saw the character: %c\n", expr[*pos]);

}

for (; expr[*pos]; (*pos)++) {

char c = expr[*pos];

if ('0' <= c && c <= '9') {

count = count * 10 + c - '0';

} else {

break;

}

}

return total(mass, count);

}

double evaluate_p(string expr, size_t limit, size_t *pos) {

char sym[4];

int sym_pos = 0;

int count = 0;

double sum = 0.0;

for (; *pos < limit && expr[*pos]; (*pos)++) {

char c = expr[*pos];

if ('A' <= c && c <= 'Z') {

if (sym_pos > 0) {

sum += total_s(sym, count);

sym_pos = 0;

count = 0;

}

sym[sym_pos++] = c;

sym[sym_pos] = 0;

} else if ('a' <= c && c <= 'z') {

sym[sym_pos++] = c;

sym[sym_pos] = 0;

} else if ('0' <= c && c <= '9') {

count = count * 10 + c - '0';

} else if (c == '(') {

if (sym_pos > 0) {

sum += total_s(sym, count);

sym_pos = 0;

count = 0;

}

(*pos)++; // skip past the paren

double mass = evaluate_p(expr, limit, pos);

sum += evaluate_c(expr, pos, mass);

(*pos)--; // neutralize the position increment

} else if (c == ')') {

if (sym_pos > 0) {

sum += total_s(sym, count);

sym_pos = 0;

count = 0;

}

(*pos)++;

return sum;

} else {

printf("Unexpected character encountered: %c\n", c);

}

}

if (sym_pos > 0) {

sum += total_s(sym, count);

}

return sum;

}

double evaluate(string expr) {

size_t limit = strlen(expr);

size_t pos = 0;

return evaluate_p(expr, limit, &pos);

}

void test(string expr) {

double mass = evaluate(expr);

printf("%17s -> %7.3f\n", expr, mass);

}

int main() {

init();

test("H");

test("H2");

test("H2O");

test("H2O2");

test("(HO)2");

test("Na2SO4");

test("C6H12");

test("COOH(C(CH3)2)3CH3");

test("C6H4O2(OH)4");

test("C27H46O");

test("Uue");

free_node(dic);

dic = NULL;

return 0;

}</lang>

{{out}}

<pre> H -> 1.008

H2 -> 2.016

H2O -> 18.015

H2O2 -> 34.014

(HO)2 -> 34.014

Na2SO4 -> 142.036

C6H12 -> 84.162

COOH(C(CH3)2)3CH3 -> 186.295

C6H4O2(OH)4 -> 176.124

C27H46O -> 386.664

Uue -> 315.000</pre>