Calc #9

ratneshkatiyar · 2020-07-17T08:57:26Z

No description provided.

alexkutsan · 2020-07-20T07:09:07Z

test/calculator_test.cpp

+        {
+            EXPECT_EQ(7.8, project_.calc("5.5 2.3 +"));
+        }
+        TEST_F(CalculatorTest, MissingOperand)


Negative and positive test cases.

alexkutsan · 2020-07-20T07:09:28Z

test/calculator_test.cpp

+        }
+        TEST_F(CalculatorTest, MissingOperand)
+        {
+            EXPECT_EQ(-1, project_.calc("5 +"));


Check a way to handle errors

alexkutsan · 2020-07-27T09:57:51Z

polishNotationCalc.cpp

@@ -46,53 +46,21 @@ namespace dev
    double PolishCalc::calc(const std::string &str)
    {
        if (str.size() == 0)
-            return 0;
+            throw Exception{"Nothing to work on as Input is empty"};
        for (int i = 0; i < str.size(); i++)


is it possible to use iterator or range based loop?

alexkutsan · 2020-07-27T09:58:35Z

polishNotationCalc.cpp

-                // {
-                //     std::cout << "calc::Exception" << e.what();
-                // }
+                res = performOperation(str[i], operandVal.first, operandVal.second);


Next step is to separate parsing and evaluating

alexkutsan · 2020-07-27T09:59:53Z

polishNotationCalc.cpp

@@ -101,4 +69,36 @@ namespace dev

        return mStack.top();
    }
+
+    void PolishCalc::pushOperandInStack(const std::string &str, int &curr_pos)


mark variable as output explicit with name curr_pos_out

return new position

alexkutsan · 2020-07-27T10:00:44Z

polishNotationCalc.cpp

+    {
+        double secOperand = 0;
+        double firstOperand = 0;
+        if (mStack.size() >= 2)


swap if condition and make early return/ throw ( safety check)

LuxoftAKutsan · 2020-07-28T08:12:59Z

polishNotationCalc.hpp

        std::stack<double> mStack;
+        std::map<const char, functionCall> mMap;


mMap bad name. Try to avoid put type name in variable, Show business value of variable

LuxoftAKutsan · 2020-07-28T08:13:42Z

polishNotationCalc.hpp

-        double performOperation(const char operation, const double firstOperand, const double secOperand);
-        void pushOperandInStack(const std::string &, int& curr_pos);
-        std::pair<double,double> getOperandFromStack();
+        void insertFunctionInsideMap();


Try to use constexpr for this.

LuxoftAKutsan · 2020-07-28T08:15:40Z

polishNotationCalc.cpp

@@ -59,7 +36,7 @@ namespace dev
            {
                auto operandVal = getOperandFromStack();
                double res = 0;
-                res = performOperation(str[i], operandVal.first, operandVal.second);
+                res = mMap[str[i]](operandVal.first, operandVal.second);


extract variable for str[i]

suggest to split implementation to parsing, validating and calculating steps

LuxoftAKutsan · 2020-07-28T08:17:42Z

polishNotationCalc.cpp

+        mMap.insert(std::make_pair('-', [](double a, double b) { return a - b; }));
+        mMap.insert(std::make_pair('*', [](double a, double b) { return a * b; }));
+        mMap.insert(std::make_pair('/', [](double a, double b) { 
+            if(b==0)


LuxoftAKutsan · 2020-07-28T08:19:52Z

polishNotationCalc.cpp

+    {
+        mMap.insert(std::make_pair('+', [](double a, double b) { return a + b; }));
+        mMap.insert(std::make_pair('-', [](double a, double b) { return a - b; }));
+        mMap.insert(std::make_pair('*', [](double a, double b) { return a * b; }));


use const as wide as you cat

LuxoftAKutsan · 2020-07-29T07:06:54Z

polishNotationCalc.cpp

+            throw Exception{"Nothing to work on as Input is empty"};
+        for (int i = 0; i < str.size(); i++)
+        {
+            if (str[i] == ' ')


avoid missing brackets even in one line if/else/while ...

LuxoftAKutsan · 2020-07-29T07:12:57Z

polishNotationCalc.cpp

+        return false;
+    }
+
+    double PolishCalc::calc( const std::string &str)


3 blocks :

1. Basic Validation // Check that the is not bad symbols and so on 2. Parsing // Use not strings, but OOP types or lambdas for futher working 2.1 Validation : count of operator matches count of operands 3. Calculation // Evaluete expression

2 stacks :
Validation block fill up 2 stacks :

Operator stack

Operand stack

Calculation should work with Operator/Operand or lambda types but not string.

LuxoftAKutsan · 2020-07-29T07:13:58Z

polishNotationCalc.cpp

+        {
+            if (str[i] == ' ')
+                continue;
+            if (isNumeric(str[i]))


Try to modify solution to work with negative numbers

LuxoftAKutsan · 2020-07-29T07:17:13Z

polishNotationCalc.cpp

+    {
+        double operand = 0;
+        std::string temp = "";
+        while (curr_pos < str.size() && !(str[curr_pos] == ' '))


In case of input like 2 4+ , solution behaviour is undefined.
Try to handle this error.
Best option is to create prevalidation function and contract for pushOperandInStack.

LuxoftAKutsan · 2020-07-29T07:18:17Z

polishNotationCalc.cpp

+                continue;
+            if (isNumeric(str[i]))
+            {
+                pushOperandInStack(str, i);


Try to work with some kind of tokens but not charters.
It is not obvious that pushOperandInStack will modify i variable. If it is possible. Try to avoid it

LuxoftAKutsan · 2020-07-29T07:20:27Z

polishNotationCalc.cpp

+                pushOperandInStack(str, i);
+
+            }
+            if (isOperator(str[i]))


Create separate loop to fill operator stack, operand stack an calculation based on 2 stacks

LuxoftAKutsan · 2020-07-29T07:21:07Z

polishNotationCalc.cpp

+            {
+                auto operandVal = getOperandFromStack();
+                double res = 0;
+                res = mOperatorMap[str[i]](operandVal.first, operandVal.second);


Move calculation to the third loop

LuxoftAKutsan · 2020-07-29T07:27:37Z

polishNotationCalc.cpp

+        if (num == '+' || num == '-' || num == '*' || num == '/')
+            return true;
+        return false;
+    }


for (from 0 to N) { Operation 1 Operation 2 Operation 3 }

for (from 0 to N) { Opertation 1 } for (from 0 to N) { Opertation 2 } for (from 0 to N) { Opertation 3 }

Both solutions have the same performance

LuxoftAKutsan · 2020-07-29T07:48:06Z

polishNotationCalc.cpp

+    {
+        insertFunctionInsideMap();
+    }
+


1 Step : Create Token stack and validate it

token_stack& = stack<Tocken> Token { // Process one tocken in the stack void process(token_stack& ) double value(const token_stack& ) << // Follow contant } NumericToken : Token { void process(token_stack& ) -> do nothing double value(token_stack& ) -> return value_ double value_ } OperatorTocken : Token { pair PopTockens } PlusTocken : OperatorTocken { void process(token_stack& ) { pop token from stack -> get value -> double res1 pop token2 from stack -> get value -> double res2 res1 + res2 -> Plus result Push plus result to token vector as Numeric } double value(const token_stack&) { // Option 1 Contract thet process() should be evaluated before value () return top of the token_stack& value() // Option 2 Base that there process() could not be called get token from stack -> get value -> double res1 get token2 from stack on the second position -> get value -> double res2 res1 + res2 -> Plus result return Plus result as double } }

3 step Go throw all tokens and call process to them

Calc unit test case

da3665e

ratneshkatiyar force-pushed the Calculator branch from f7c8c12 to da3665e Compare July 19, 2020 09:26

alexkutsan reviewed Jul 20, 2020

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rkatiyar added 4 commits July 20, 2020 11:14

Implementation of polishCalc

1db6fc8

Add Exception class

a7fa1dd

Add const and value by reference

19a9b77

Refactoring: Add newfunction

a38c473

alexkutsan reviewed Jul 27, 2020

View reviewed changes

refactor: remove switch conditions

4dfa118

LuxoftAKutsan reviewed Jul 28, 2020

View reviewed changes

Add const and variable name change

6a5cc3d

LuxoftAKutsan reviewed Jul 29, 2020

View reviewed changes

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Calc #9

Calc #9

ratneshkatiyar commented Jul 17, 2020

alexkutsan Jul 20, 2020

alexkutsan Jul 20, 2020

alexkutsan Jul 27, 2020

alexkutsan Jul 27, 2020

alexkutsan Jul 27, 2020

alexkutsan Jul 27, 2020

LuxoftAKutsan Jul 28, 2020

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LuxoftAKutsan Jul 28, 2020

LuxoftAKutsan Jul 28, 2020

LuxoftAKutsan Jul 28, 2020 •

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LuxoftAKutsan Jul 29, 2020

LuxoftAKutsan Jul 29, 2020 •

edited

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		std::stack<double> mStack;
		std::map<const char, functionCall> mMap;

Calc #9

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Calc #9

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ratneshkatiyar commented Jul 17, 2020

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LuxoftAKutsan Jul 28, 2020 • edited Loading

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LuxoftAKutsan Jul 29, 2020 • edited Loading

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LuxoftAKutsan Jul 28, 2020 •

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