Calculator with parentheses

Calculator with parentheses

// This calculator supports the brackets function. The format Example 3 + (3*3) # is followed by two # The calculation is complete, and features such as factorial and power are left to the students for improvement.
# Include <iostream> using namespace std; template <typename T> struct Node {// This is a data structure template. Both char and int can use T data; node <T> * next;}; template <typename T> class stack {Node <T> * top; public: stack (): top (NULL) {} void push (T n); T pop (); bool stackEmpty (); T getTop ();~ Stack () {} void print () ;}; template <typename T> void stack <T>: push (T n) {Node <T> * r = new Node <T>; r-> data = n; r-> next = top; top = r ;} template <typename T> T stack <T>: pop () {Node <T> * ptr = top; top => next; T t = ptr-> data; delete ptr; return t;} template <typename T> void stack <T>: print () {for (Node <T> * p = top; p; p = p-> next) cout <p-> data <"";} template <typename T> T stack <T >:: getTop () {return top-> data;} templa Te <typename T> bool stack <T>: stackEmpty () {if (top) return false; else return true;} bool In (char t) {// determine whether the character function if (t> = '0' & t <= '9') return false; else return true;} char Precede (char, char B) {operator priority function if (a = '(' & B = ')' | a = '#' & B = '#') return '= '; else if (a = '(' | a = '#' | B = '(' | (a = '+' & a =' -') & (B = '*' | B = '/') return '<'; else return '>';} int Operate (int first, char t, int second) {// operation function switch (T) {case '+': return first + second; case '-': return first-second; case '*': return first * second; case '/': return first/second;} return 0;} int EvaluateExpression () {char theta, x; int a, B; stack <char> OPTR; // operator stack <int> OPND; // number OPTR. push ('#'); string s; cin> s; for (int I = 0; I <s. length ()-1;) {if (! In (s [I]) {int sum = s [I]-'0'; I ++; (;! In (s [I]) & I <s. length ()-1; I ++) {int t = s [I]-'0'; sum = sum * 10 + t;} OPND. push (sum);} // If the ch is not an operator, it enters the OPND stack else switch (Precede (OPTR. getTop (), s [I]) {// compare the top element of the OPTR stack and the priority case of ch '<': // press the current character ch into the OPTR stack, read the next character ch OPTR. push (s [I]); I ++; break; case '>': // The operator at the top of the OPTR stack is displayed for calculation, and import the calculation result to the stack theta = OPTR. pop (); a = OPND. pop (); B = OPND. pop (); OPND. push (Operate (B, theta, a); break; case '=': x = OPTR. pop (); I ++; break;} // switch} // while return OPND. pop () ;}int main () {cout <"shuaicheng calculator supports brackets. Format: (expression ###) Example: 2 + 2 ##" <endl; for (;) {cout <EvaluateExpression (); cout <endl;} return 0 ;}