C Tricks（十三）—— trim 的实现

void trim(const char exp[], int& lo, int& hi, char c = ' '){
while (lo <= hi && exp[lo] == c) ++lo;
while (lo <= hi && exp[hi] == c) --hi;
}

(

)

void trim(const char exp[], int& lo, int& hi) {
while (lo <= hi && exp[lo] != '(' && exp[lo] != ')') ++lo;
while (lo <= hi && exp[hi] != '(' && exp[hi] != ')') --hi;
}