Java implements the inverse Polish Calculator

Package COM. CZP; import Java. util. hashmap; import Java. util. stack; public class calculator {// operator priority Private Static hashmap <string, integer> opls; private string SRC; Public calculator (string SRC) {This. src = SRC; If (opls = NULL) {opls = new hashmap <string, integer> (6); opls. put ("+", 0); opls. put ("-", 0); opls. put ("*", 1); opls. put ("/", 1); opls. put ("%", 1); opls. put (")", 2) ;}// convert the infix expression to the suffix expression Public String torpn () {string [] TMP = Split (SRC); // suffix stack <string> RPN = new stack <string> (); // temporary stack <string> tmpsta = new stack <string> (); For (string STR: TMP) {If (isnum (STR) {// is the operand, directly press the result stack RPN. push ('+ STR +');} else {// operation symbol if (tmpsta. isempty () {// There is no tmpsta symbol. push (STR);} else {// judge the priority of the current symbol and the temporary stack top symbol if (ishigh (tmpsta. peek (), STR) {If (! Str. equals (")") {do {// 1 find the operator that is earlier than the current priority in the temporary stack // 2 press into the current read operator RPN. push (tmpsta. peek (); tmpsta. pop () ;}while (! Tmpsta. isempty () & (ishigh (tmpsta. peek (), STR); tmpsta. push (STR);} else {// yes) pop up the data of the temporary stack in sequence until (until the while (! Tmpsta. isempty ()&&! Tmpsta. Peek (). Equals ("(") {RPN. Push (tmpsta. Pop ();} If ((! Tmpsta. empty () & (tmpsta. peek (). equals ("(") {// pop-up (tmpsta. pop () ;}} else if (! Ishigh (tmpsta. Peek (), STR) {tmpsta. Push (STR) ;}}} while (! Tmpsta. empty () {// pops up the remaining operators in the stack in RPN. push (tmpsta. pop ();} stringbuilder ST = new stringbuilder (); For (string STR: RPN) {St. append (STR);} RPN. clear (); Return St. tostring ();} // split (56 + 4) 3*6 + 2 => (, 56, +, 4, private string [] Split (string SRC) {stringbuilder sb = new stringbuilder (SRC. length (); For (char CH: SRC. tochararray ()) {If (CH = '+' | CH = '-' | CH = '*' | CH = '/ '| CH =' ('| CH = ') '| CH =' % ') {sb. append ("," ); Sb. append (CH); sb. append (",");} else {sb. append (CH) ;}string string = sb. tostring (). replaceall (", {2,}", ","); Return string. split (",") ;}// comparison operator priority private Boolean ishigh (string pop, string Str) {If (Str. equals (")") return true; If (opls. get (POP) = NULL | opls. get (STR) = NULL) return false; return opls. get (POP)> = opls. get (STR) ;}// whether the number is public Boolean isnum (string Str) {for (char CH: Str. tochararray () {If (CH = '+' | CH = '-' | CH = '*' | CH = '/' | ch = '(' | CH = ') '| CH =' % ') return false;} return true;} // obtain the public double getres () {string RPN = torpn (); stack <double> res = new stack <double> (); stringbuilder sb = new stringbuilder (); For (char CH: RPN. tochararray () {If (CH = '(') {continue ;} else if (CH> = '0' & Ch <= '9' | CH = '. ') {sb. append (CH);} else if (CH = ') {res. push (double. valueof (sb. tostring (); sb = new stri Ngbuilder ();} else {If (! Res. empty () {Double X = res. pop (); Double Y = res. pop (); Switch (CH) {Case '+': Res. push (Y + x); break; Case '-': Res. push (Y-x); break; Case '*': Res. push (y * X); break; Case '%': Case '/': If (X! = 0) {double RSD = CH = '% '? Y % x: Y/X; Res. push (RSD);} else {system. out. println ("Zero Denominator"); Res. clear (); Return-1;} break; }}} double result = res. pop (); Res. clear (); return result;} public static void main (string [] ARGs) {string src2 = "156899 + 5*(36 + 5)-8% 3 "; calculator analyer = new calculator (src2); system. out. println (src2 + "=" + analyer. getres ());}}