Java string formula calculation --- reprint

Import java. Lang. Reflect. method;
Import java. util. arraylist;
Import java. util. hashmap;
Import java. util. List;
Import java. util. Map;
/**
* A string expression can be computed simply by using functions.
* @ Author
*/
Public class analyzecalculate {
/**
* Defining Operators
*/
Public static list <string> lc = new arraylist <string> ();
Static {
LC. Add ("+ ");
LC. Add ("'");
LC. Add ("*");
LC. Add ("/");
}
/**
* Define logical operators
*/
Public static list <string> lj = new arraylist <string> ();
Static {
LJ. Add ("> ");
LJ. Add ("<");
LJ. Add ("= ");
LJ. Add ("! ");
}
/**
* Int array comment, first identifier: 0 built-in function 1 custom function; second identifier: number of parameters
*/
Public static Map <string, int []> funmap = new hashmap <string, int []> ();
Static {
// Built-in function, which can be reflected
Funmap. Put ("ABS", new int [] {0, 1 });
Funmap. Put ("ACOs", new int [] {0, 1 });
Funmap. Put ("asin", new int [] {0, 1 });
Funmap. Put ("atan", new int [] {0, 1 });
Funmap. Put ("cbrt", new int [] {0, 1 });
Funmap. Put ("Ceil", new int [] {0, 1 });
Funmap. Put ("Cos", new int [] {0, 1 });
Funmap. Put ("cosh", new int [] {0, 1 });
Funmap. Put ("exp", new int [] {0, 1 });
Funmap. Put ("expm1", new int [] {0, 1 });
Funmap. Put ("floor", new int [] {0, 1 });
Funmap. Put ("log", new int [] {0, 1 });
Funmap. Put ("log10", new int [] {0, 1 });
Funmap. Put ("log1p", new int [] {0, 1 });
Funmap. Put ("random", new int [] {0, 1 });
Funmap. Put ("RINT", new int [] {0, 1 });
Funmap. Put ("round", new int [] {0, 1 });
Funmap. Put ("SIGNUM", new int [] {0, 1 });
Funmap. Put ("sin", new int [] {0, 1 });
Funmap. Put ("Sinh", new int [] {0, 1 });
Funmap. Put ("SQRT", new int [] {0, 1 });
Funmap. Put ("Tan", new int [] {0, 1 });
Funmap. Put ("Tanh", new int [] {0, 1 });
Funmap. Put ("Max", new int [] {0, 2 });
Funmap. Put ("min", new int [] {0, 2 });
// User-Defined Functions
Funmap. Put ("if", new int [] {1, 3 });
Funmap. Put ("Mod", new int [] {1, 2 });
Funmap. Put ("int", new int [] {1, 1 });
}

/**
* Formula initialization and conversion
*
* @ Param Str
* @ Return indicates the processed computing client string.
*/
Public static string strcast (string Str ){
STR = Str. tolowercase (); // remove spaces and write less

If (STR = NULL? True: Str. Length () = 0)
Return "0 ";
If (! Checkformula (STR ))
Return "0 ";
STR = Str. replaceall ("\\*-","**");
STR = Str. replaceall ("-\\*","**");
STR = Str. replaceall ("/-","//");
STR = Str. replaceall ("-/","//");
STR = Str. replaceall ("\\+ -","-");
STR = Str. replaceall ("-\ + ","-");
STR = Str. replaceall ("-","'");
STR = Str. replaceall ("\\*\\*","*-");
STR = Str. replaceall ("//","/-");
STR = Str. replaceall ("","");
Return STR;
}

/**
* Check whether the number of parentheses in the formula is correct.
*
* @ Param formulastr
* @ Return indicates whether parentheses in the formula are paired.
*/
Public static Boolean checkformula (string formulastr ){
Boolean flag = true;
Int COUNT = 0;
For (INT I = 0; I <formulastr. Length (); I ++ ){
String S = string. valueof (formulastr. charat (I ));
If ("(". Equals (s ))
Count ++;
Else if (")". Equals (s ))
Count --;
}
Flag = COUNT = 0;
Return flag;
}

/**
* Split Functions
*
* @ Param Str
* @ Param BS
* @ Return refers to the split string.
*/
Public static string [] splitefun (string STR, string BS ){
List <string> List = new arraylist <string> ();
String BDS = "";
Int bracket = 0;
Int Len = Str. Length ();
For (INT I = 0; I <Len; I ++ ){
String S = string. valueof (Str. charat (I ));
If ("(". Equals (s )){
Bracket ++;
} Else if (")". Equals (s )){
Bracket --;
}

If (bracket = 0 & BS. Equals (s )){
List. Add (BDS );
BDS = "";
Continue;
}

BDS + = s;
}

List. Add (BDS );

String [] Ss = new string [list. Size ()];
For (INT I = 0; I <list. Size (); I ++ ){
Ss [I] = list. Get (I );
}

Return SS;
}

/**
* User-Defined Functions
*
* @ Param Str
* @ Param funstr
* @ Return process user-defined functions
*/
Public static string customfun (string STR, string funstr ){
String reval = "0 ";

String [] GSS = splitefun (STR ,",");
If ("if". Equals (funstr )){
If (compare (GSS [0]) {
Reval = calculate (GSS [1]);
} Else {
Reval = calculate (GSS [2]);
}
} Else if ("Mod". Equals (funstr )){
Double D2 = new double (calculate (GSS [1]);
If (d2 = 0)
Return reval;
Double d1 = new double (calculate (GSS [0]);
Reval = (d1% D2) + "";
} Else if ("int". Equals (funstr )){
Reval = math. Floor (New Double (calculate (GSS [0]) + "";
}
Return reval;
}

/**
* Logical expression judgment
* @ Param Str
* @ Return true or false
*/
Public static Boolean compare (string Str ){
Boolean flag = false;
Boolean BS = false;
Int Len = Str. Length ();
Int bracket = 0;
String ljbds = "";
Double d_left = 0;
Double d_right = 0;

For (INT I = 0; I <Len; I ++ ){
String S = string. valueof (Str. charat (I ));
If ("(". Equals (s )){
Bracket ++;
} Else if (")". Equals (s )){
Bracket --;
}

If (bracket = 0 & LJ. Contains (s )){
For (Int J = I; j <Len; j ++ ){
String Ts = string. valueof (Str. charat (j ));
If (LJ. Contains (TS )){
Ljbds + = ts;
} Else {
BS = true;
Break;
}
}
}
If (BS)
Break;
}

String [] S = Str. Split (ljbds );
D_left = new double (calculate (s [0]);
D_right = new double (calculate (s [1]);

If ("<". Equals (ljbds )){
If (d_left <d_right)
Return true;
} Else if (">". Equals (ljbds )){
If (d_left> d_right)
Return true;
} Else if ("=". Equals (ljbds )){
If (d_left = d_right)
Return true;
} Else if ("> =". Equals (ljbds )){
If (d_left> = d_right)
Return true;
} Else if ("<=". Equals (ljbds )){
If (d_left <= d_right)
Return true;
} Else if ("<>". Equals (ljbds) | "! = ". Equals (ljbds )){
If (d_left! = D_right)
Return true;
}

Return flag;
}

/**
* Recursive call operation
*
* @ Param Str
* @ Return string
*/
Public static string calculate (string Str ){

String reval = "";
String BDS = "";
Int bracket = 0; // Number of parentheses
Int Pos = 0;
Boolean Title = false;

If (Str. substring (0, 1). Equals ("'")){
STR = Str. substring (1 );
Title = true;
}

Int Len = Str. Length ();

For (INT I = 0; I <Len; I ++ ){
String S = string. valueof (Str. charat (I ));
Pos = I;
Bracket = 0;
If (! LC. Contains (s) {// if no operator is encountered
If ("(". Equals (s) {// if left parentheses are encountered
If (funmap. containskey (BDS) {// If the left bracket is a function
For (Int J = I + 1; j <Len; j ++) {// starts the loop after the left parenthesis
Pos ++; // Accumulative number of characters to be moved
String Ts = string. valueof (Str. charat (j); // a single character
// Reval + = ts;
If ("(". Equals (TS) // if it is left parenthesis cumulative
Bracket ++;
Else if (")". Equals (TS) {// if it is a right brace, reduce it.
Bracket --;
If (bracket =-1) {// if it is-1, the end of the brackets
Reval = reval. substring (0, Reval. Length ()
-BDS. Length (); // obtain the expression that removes the function header again.
Reval + = funcalculate (Str. substring (I + 1,
J), BDS); // Add the function result to the expression to form a new expression.
I = Pos; // the counter is added.
BDS = ""; // clear the function Header
Break; // exit this cycle
}
}
}
} Else {// for normal operations
For (Int J = I + 1; j <Len; j ++ ){
Pos ++;
String Ts = string. valueof (Str. charat (j ));
If ("(". Equals (TS ))
Bracket ++;
Else if (")". Equals (TS )){
Bracket --;
If (bracket =-1 ){
Reval + = calculate (Str
. Substring (I + 1, POS ));
I = Pos;
BDS = "";
Break;
}
}
}
}
} Else {// sum of the total expression and the number of the last operation (or function)
BDS + = s;
Reval + = s;
}
} Else {// the last number (or function) of the operator is cleared.
BDS = "";
Reval + = s;
}
}

If (title)
Reval = "-" + reval;
Return szys (reval );
}

/**
* Function operations
*
* @ Param GS
* @ Param flag
* @ Return string
*/
Public static string funcalculate (string Gs, string funstr ){
String rval = "0 ";
If (funmap. containskey (funstr )){
Int [] CSI = funmap. Get (funstr );
Try {
If (CSI [0] = 0) {// Java internal function, called through reflection
Class [] cs = new class [CSI [1];
Object [] objs = new object [CSI [1];
String [] GSS = zlcs (GS );
For (INT I = 0; I <CSI [1]; I ++ ){
CS [I] = double. Class;
Objs [I] = new double (calculate (GSS [I]);
}
Class CLS = Class. forname ("Java. Lang. Math ");
Method M = Cls. getmethod ("ABS", CS );
Rval = string. valueof (M. Invoke (CLS, objs ));
} Else if (CSI [0] = 1) {// User-Defined Function
Rval = customfun (GS, funstr );
}
} Catch (exception e ){

}
}

Return rval;
}

/**
* Parameter segmentation in the formula
* @ Param Str
* @ Return string []
*/
Public static string [] zlcs (string Str ){
Int Len = Str. Length ();
Boolean flag = true;
String tstr = "";

For (INT I = 0; I <Len; I ++ ){
String S = string. valueof (Str. charat (I ));
If ("(". Equals (s )){
Flag = false;
} Else if (")". Equals (s )){
Flag = true;
}
If (flag & ",". Equals (s )){
Tstr + = "@";
} Else {
Tstr + = s;
}
}

Return tstr. Split ("@");

}

/**
* Four arithmetic expressions
*
* @ Param Str
* @ Return string
*/
Public static string szys (string GS ){
GS = GS + "+ 0"; // because the following computation is performed only when a symbol is encountered, adding one more computation symbol does not affect the value.
String C1 = ""; // The First operator number
String C2 = ""; // The second operator number.
String S1 = ""; // number of the first operation
String S2 = ""; // The second operation count.
String S3 = ""; // The third operation count.

Int Len = Gs. Length ();
For (INT I = 0; I <Len; I ++ ){
String S = string. valueof (Gs. charat (I); // obtain the character at this position and convert it to a string for comparison.

If (LC. Contains (s) {// if it is an operator number
If (c1.length () = 0) // if the first operator is null, add
C1 = s;
Else if (c2.length () = 0) {// otherwise, if the second operator is null, add
C2 = s; // The second operator number.
If ("+". Equals (C2) | "'". Equals (C2) {// if the level of the second operator is low, the calculation is performed.
S1 = _ 4zys (S1, C1, S2); // calculate the first and second numbers
C1 = c2; // Save the second operator. The other operator is null.
C2 = "";
S2 = "";
}
} Else {// all the above are saved
If ("+". Equals (s) | "'". Equals (s) {// if the third operator is low, perform operations
S2 = _ 4zys (S2, C2, S3); // calculate the number of the second three and save it to the second one.
S1 = _ 4zys (S1, C1, S2); // calculate the first two and save it to the first one.
C1 = s; // Save the current operator. Other values are empty.
S2 = "";
C2 = "";
S3 = "";
} Else {// if the third operator is of a high level
S2 = _ 4zys (S2, C2, S3); // calculate the number of the second three and save it to the second one.
C2 = s; // the operator is not moved.
S3 = "";
}
}
} Else if (s1.length ()> 0 & c1.length ()> 0 & c2.length () = 0) {// if the first number is, the first operator is saved, the second operator is not saved. The second operator is saved.
S2 + = s;
} Else if (c1.length () = 0) {// if no operator exists, save the first number
S1 + = s;
} Else if (s1.length ()> 0 & s2.length ()> 0 & c1.length ()> 0
& C2.length ()> 0) {// if both the first and second numbers and operators exist, save the third number
S3 + = s;
}
}
Return S1;
}

/**
* Four basic arithmetic operations
*
* @ Param C1
* Operation count 1
* @ Param S1
* Operator (addition, subtraction, multiplication, division)
* @ Param C2
* Operation count 2
* @ Return string
*/
Public static string _ 4zys (string C1, string S1, string C2 ){
String reval = "0 ";

Try {
Double Ln = double. valueof (C1). doublevalue ();
Double Rn = double. valueof (C2). doublevalue ();
If ("+". Equals (S1 )){
Return (LN + rn) + "";
} Else if ("'". Equals (S1 )){
Return (Ln-Rn) + "";
} Else if ("*". Equals (S1 )){
Return (LN * rn) + "";
} Else if ("/". Equals (S1 )){
If (Rn = 0)
Return reval;
Else
Return (Ln/RN) + "";
}
} Catch (exception e ){
} Finally {
}

Return reval;
}

/**
* Test
* @ Param ARGs
*/
Public static void main (string [] ARGs ){

String GS = "If (4> 3, if (2-1)/(0.0001) * 3> 3, (2-(2-1)/(0.0001) * 3) * 0.8, 0), (2 + (3-2)/(0.0001) * 1) * 1 )";
// Perform four arithmetic operations to obtain the result
System. Out. println (szys (strcast ("3-4 *-5 + 5 ")));
System. Out. println (calculate (strcast ("3-4 *-5 + 5 ")));
// Function operation result
System. Out
. Println (calculate (strcast ("3 + ABS (mod (4, if (2> 3, 1, 3)-ABS (2*4 )) * 5 + 5 ")));

System. Out. println (calculate (strcast ("If (0.0*2> = 10.0, 0, 10.0-0.0*2 )")));

System. Out. println (calculate (strcast ("If (0 <2, (10.0-0*5) * 0.8, 0 )")));

System. Out. println (calculate (strcast ("-10/0 ")));

}

}