bool calcMul(double &result, int &curLex, char lexemeString []) {
bool isNegative = false;
if (curLex == add || curLex == take) {
isNegative = curLex == take;
nextLexeme(curLex, lexemeString);
}
switch (curLex) {
case number: {
result = toNum(lexemeString);
nextLexeme(curLex, lexemeString);
break;
}
case open:{
nextLexeme(curLex, lexemeString);
if (!calcExp(result, curLex, lexemeString))
return false;
if (curLex != close)
return false;
nextLexeme(curLex, lexemeString);
break;
}
}
result *= isNegative ? -1 : 1;
return true;
}
int main() {
int curLex = start;
char lexemeString[10] = { '/0' };
double result = 0.0;
nextLexeme(curLex, lexemeString);
if (calcExp(result, curLex, lexemeString))
printf("%0.3f\n", result);
else
printf("wrong expression\n");
return 0;
}
bool calcTerm(double &result, int &curLex, char lexemeString []) {
if (!calcMul(result, curLex, lexemeString))
return false;
while (curLex == multiplication || curLex == division) {
int operation = curLex;
double next = 0.0;
nextLexeme(curLex, lexemeString);
if (!calcMul(next, curLex, lexemeString))
return false;
switch (operation) {
case multiplication: {
result *= next;
break;
}
case division:{
result /= next;
break;
}
}
}
return true;
}
bool calcExp(double &result, int &curLex, char lexemeString []) {
if (!calcTerm(result, curLex, lexemeString))
return false;
while (curLex == add || curLex == take) {
int operation = curLex;
nextLexeme(curLex, lexemeString);
double next = 0.0;
if (!calcTerm(next, curLex, lexemeString))
return false;
switch (operation) {
case add: {
result += next;
break;
}
case take: {
result -= next;
break;
}
}
}
return curLex == finish || curLex == close;
}
int test_nextLexeme(char *s, ...){
int length;
int type;
int testType;
va_list args;
va_start(args, s);
printf("[\n");
while(!nextLexeme(s, &length, &type)){
testType = va_arg(args, int);
printf("\t{type:%d, typeName:\"%s\", lexeme:\"", type, LEXEMETYPE_STRINGS[type]);
puts_escaped(s, s+length);
printf("\"},\n");
s += length;
if(testType != type){
printf("types don't match!\n");
exit(1);
}
}
printf("]\n");
return 0;
}
