int evaluate(FILE *fout, const char *expr)
{
//parse the expression
tokenNode *infix = createTokenNode();
addAfterTokenNode(infix);
if (!parse(expr, infix)) {
fprintf(stderr, "Parsing failed\n");
return 0;
}
//a flag for the +, -
int previsnum = 0;
initOperPriority();
//calculate
for (tokenNode *i = infix->next; i->token != NULL; i = i->next) {
char *endptr = NULL;
long long thisNumber = createNumber(i->token, &endptr);
if (readNumErr) {
fprintf(stderr, "Failed reading a number\n");
freeAllTokenNodes(infix);
return 0;
}
if (endptr != i->token) {
pushNum(createFraction(thisNumber, 1));
previsnum = 1;
} else {
char oper = i->token[0];
switch (oper) {
case '_':
pushNum(lastResult);
previsnum = 1;
break;
case '(':
pushOper(oper);
previsnum = 0;
break;
case ')':
if(!calculatingCycle()) {
fprintf(stderr, "Calculating failed\n");
freeAllTokenNodes(infix);
return 0;
}
//pop the (
popOper();
previsnum = 0;
break;
default:
//dealing with the signs
if (!previsnum) {
if (oper == '+') {
oper = 'P';
} else if (oper == '-') {
oper = 'N';
}
}
//there is an operator at the top of the stack
if (operNum) {
//compare the priorities of oper and topOper
if (operPriority[(int)oper] < operPriority[(int)getTopOper()]) {
//pop all and calc
if(!calculatingCycle()) {
fprintf(stderr, "Calculating failed\n");
freeAllTokenNodes(infix);
return 0;
}
pushOper(oper);
} else if (oper != 'P' && oper != 'N' && operPriority[(int)oper] == operPriority[(int)getTopOper()]) {
//pop one and calc to ensure the calulation is done l2r
//the P and N (aka +, -) are done r2l
if(!calculate()) {
fprintf(stderr, "Calculating failed\n");
freeAllTokenNodes(infix);
return 0;
}
pushOper(oper);
} else {
pushOper(oper);
}
//the operator stack is empty
} else {
pushOper(oper);
}
previsnum = 0;
break;
}
}
}
//pop the left operators and calc
if(!calculatingCycle()) {
fprintf(stderr, "Calculating failed\n");
freeAllTokenNodes(infix);
return 0;
}
//pop the result
Fraction *result = NULL;
switch (numNum) {
case 0:
fprintf(stderr, "Get no result\n");
freeAllTokenNodes(infix);
return 0;
case 1:
result = popNum();
lastResult = *result;
fprintf(fout, "%lld", result->numerator);
if (result->denominator != 1) {
fprintf(fout, "/%lld\n", result->denominator);
} else {
fputc('\n', fout);
}
break;
default:
fprintf(stderr, "Get multiple results\n");
freeAllTokenNodes(infix);
return 0;
}
freeAllTokenNodes(infix);
return 1;
}
char * calc(char * exp)
{
Stack * num_stack = initStackNum(strlen(exp));
Stack * oper_stack = initStackOper(strlen(exp));
int i;
int bool_num = 0;
int bool_min = 0;
int cursor;
double res = 0;
char ch;
double numVal;
char * num = calloc(strlen(exp), sizeof(char));
for (i = 0; i < strlen(exp); ++i)
{
if (exp[i] >= '0' && exp[i] <= '9' || exp[i] == '.')
{
if (bool_num == 0)
{
bool_num = 1;
cursor = 0;
}
else
{
cursor++;
}
num[cursor] = exp[i];
num[cursor+1] = '\0';
}
else if (exp[i] == '+' || exp[i] == '-')
{
if (bool_num == 1)
{
char oper = exp[i];
double number = atof(num);
if (bool_min > 0)
{
bool_min = 0;
number = -number;
}
if (getCursorOper() >= 0)
{
if (!topOper(oper_stack, &ch))
return NULL;
if (ch == '*')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal * number;
}
else if (ch == '/')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal / number;
}
}
if (oper == '-')
{
oper = '+';
bool_min = 1;
}
if (!pushNum(num_stack, number))
return NULL;
int j;
for (j = 0; j < cursor+1; ++j)
{
num[j] = '\0';
}
bool_num = 0;
if (!pushOper(oper_stack, oper))
return NULL;
}
else
{
return NULL;
}
}
else if (exp[i] == '*' || exp[i] == '/')
{
if (bool_num == 1)
{
double number = atof(num);
if (bool_min > 0)
{
bool_min = 0;
number = -number;
}
if (getCursorOper() >= 0)
{
if (!topOper(oper_stack, &ch))
return NULL;
if (ch == '*')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal * number;
}
else if (ch == '/')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal / number;
}
}
if (!pushNum(num_stack, number))
return NULL;
int j;
for (j = 0; j < cursor+1; ++j)
{
num[j] = '\0';
}
bool_num = 0;
if (!pushOper(oper_stack, exp[i]))
return NULL;
}
else
{
return NULL;
}
}
else
{
return NULL;
}
if (i == strlen(exp) - 1)
{
if (strlen(num) > 0)
{
double number = atof(num);
if (bool_min > 0)
{
bool_min = 0;
number = -number;
}
if (getCursorOper() >= 0)
{
if (!topOper(oper_stack, &ch))
return NULL;
if (ch == '*')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal * number;
}
else if (ch == '/')
{
popOper(oper_stack, &ch);
if (!popNum(num_stack, &numVal))
return NULL;
number = numVal / number;
}
}
if (!pushNum(num_stack, number))
return NULL;
int j;
for (j = 0; j < cursor+1; ++j)
{
num[j] = '\0';
}
bool_num = 0;
}
else
{
return NULL;
}
}
}
while (getCursorNum() > 0 && getCursorOper() >= 0)
{
double second;
if(!popNum(num_stack, &second))
return NULL;
double first;
if(!popNum(num_stack, &first))
return NULL;
char oper;
if (!popOper(oper_stack, &oper))
return NULL;
if (oper == '+')
{
double tmp_res = first + second;
if(!pushNum(num_stack, tmp_res))
return NULL;
}
else if (oper == '-')
{
double tmp_res = first - second;
if (!pushNum(num_stack, tmp_res))
return NULL;
}
}
if (!popNum(num_stack, &res))
return NULL;
char buff [100];
sprintf(buff,"%f", res);
char * chres = malloc(sizeof(char)*strlen(buff));
strcpy(chres, buff);
return chres;
}