Calculator works

modules/Archimedes-Modules/Calculator/Calculator.cpp

@@ -43,90 +43,199 @@ void Calculator::run() {
     }
 
 }
+        
+void Calculator::index(std::string equation, std::unordered_map<unsigned int, std::string>& nodes) {
+    unsigned int idx = 0;
 
-std::string calculate(std::string equation) {
+    nodes.clear();
-    std::stringstream s(equation);
+
+    const static std::string operators[] = {
+        "(",
+        ")",
+        "^",
+        "*",
+        "/",
+        "+",
+        "-"
+    };
+
+    for(const std::string& s : operators) {
+
+        while(equation.find(s, idx) != std::string::npos) {
+            int next = equation.find(s, idx);
+            nodes[next] = equation.substr(next, s.length());
+            idx = next + s.length();
+        }
+        idx = 0;
+    }
+
+
+    // -3+8*6-(8+4)^9/5
+    for(unsigned int i = 0; i < equation.length(); i++) {
+        static unsigned int begin = 0, end = 0;
+        if(nodes.find(i) == nodes.end()) {
+            if(nodes.find(i - 1) != nodes.end() || i == 0) {
+                //first digit of expression
+                begin = i;
+            }
+            if(nodes.find(i + 1) != nodes.end() || i == equation.length() - 1) {
+                //character after last digit of expression
+                end = i + 1;
+                nodes[begin] = equation.substr(begin, end - begin);
+                nodes[end - 1] = equation.substr(begin, end - begin);
+            }
+        }
+    }
+}
+
+double Calculator::evaluate(std::string equation, std::unordered_map<char, std::string>& evalStr) {
+
+    char op = '^';
+
+    while(equation.find(op) == std::string::npos) {
+        switch(op) {
+            case '^':
+                op = '*';
+                break;
+            case '*':
+                op = '/';
+                break;
+            case '/':
+                op = '+';
+                break;
+            case '+':
+                op = '-';
+                break;
+            case '-':
+                //no operator
+                if(evalStr.find(equation.front()) != evalStr.end()) {
+                    return evaluate(evalStr[equation.front()], evalStr);
+                } else {
+                    return std::stod(equation);
+                }
+                break;
+        }
+    }
+    //op is now the appropriate operator
+
+    //if either term is a placeholder, evaluate and substitute.
+    double a, b;
+    if(evalStr.find(equation.front()) != evalStr.end()) {
+        a = evaluate(evalStr[equation.front()], evalStr);
+    } else {
+        if(equation.find(op) == 0 && op == '-') {
+            a = 0;
+        } else {
+            a = std::stod(equation.substr(0, equation.find(op)));
+        }
+    }
+
+    if(evalStr.find(equation.back()) != evalStr.end()) {
+        b = evaluate(evalStr[equation.back()], evalStr);
+    } else {
+        b = std::stod(equation.substr(equation.find(op) + 1));
+    }
+    switch(op) {
+        case '^':
+            return pow(a, b);
+        case '*':
+            return a * b;
+        case '/':
+            return a / b;
+        case '+':
+            return a + b;
+        case '-':
+            return a - b;
+    }
+}
+
+std::string Calculator::calculate(std::string equation) {
     
     //PEMDAS
-    while(equation.find('(') != std::string::npos) {
+    while(equation.find(' ') != std::string::npos) {
-        if(equation.find(')') == std::string::npos) {
+        equation.erase(equation.find(' '), 1);
-            return "error";
-        }
-
-        int start = equation.find_last_of('(');
-        int end = equation.find_first_of(')', start);
-
-        std::string insert = calculate(equation.substr(start + 1, end - 1));
-
-        equation.replace(start, end, insert.c_str());
-
     }
 
-    while(equation.find('^') != std::string::npos) {
+    std::unordered_map<unsigned int, std::string> nodes;
+    std::unordered_map<char, std::string> evalStr;
+    std::string eval = "a";
+
+    unsigned int idx = 0;
+
+    index(equation, nodes);
+
+    idx = 0;
+
+    // ()
+    while(equation.find(')', idx) != std::string::npos) {
+        int end = equation.find(')');
+        int begin = equation.rfind('(', end);
+        evalStr[eval.front()] = calculate(equation.substr(begin + 1, (end - begin) - 1));
+        equation.replace(begin, (end - begin) + 1, eval);
+        eval.front()++;
+        idx = end + 1;
+    }
+    idx = 0;
+    index(equation, nodes);
+    // ^
+    while(equation.find('^', idx) != std::string::npos) {
         int mid = equation.find('^');
-        int start = equation.rfind(' ', mid - 1);
+        int begin = equation.find(nodes[mid - 1] + nodes[mid]);
-        int end = equation.find(' ', mid + 1);
+        int end = equation.find(nodes[mid] + nodes[mid + 1], begin) + (nodes[mid] + nodes[mid + 1]).length();
-        double base = stod(equation.substr(start + 1, mid - 1));
+        evalStr[eval.front()] = equation.substr(begin, end - begin);
-        double exp = stod(equation.substr(mid + 1, end - 1));
+        equation.replace(begin, end - begin, eval);
-
+        eval.front()++;
-        std::string insert = std::to_string(pow(base, exp));
+        idx = end + 1;
-        
-        equation.replace(start, end, insert.c_str());
-
     }
-    while(equation.find('*') != std::string::npos) {
+    idx = 0;
-        int mid = equation.find('*');
+    index(equation, nodes);
-        int start = equation.rfind(' ', mid - 1);
+    // * or /
-        int end = equation.find(' ', mid + 1);
+    while(equation.find('*', idx) != std::string::npos || equation.find('/', idx) != std::string::npos) {
-        double a = stod(equation.substr(start + 1, mid - 1));
+        if(equation.find('*', idx) < equation.find('/', idx) && equation.find('*', idx) != std::string::npos) {
-        double b = stod(equation.substr(mid + 1, end - 1));
+            int mid = equation.find('*');
-        
+            int begin = equation.find(nodes[mid - 1] + nodes[mid]);
-        std::string insert = std::to_string(a * b);
+            int end = equation.find(nodes[mid] + nodes[mid + 1], begin) + (nodes[mid] + nodes[mid + 1]).length();
-        
+            evalStr[eval.front()] = equation.substr(begin, end - begin);
-        equation.replace(start, end, insert.c_str());
+            equation.replace(begin, end - begin, eval);
-
+            eval.front()++;
-    }
+            idx = end + 1;
-    while(equation.find('/') != std::string::npos) {
+        } else if(equation.find('/', idx) != std::string::npos) {
-        int mid = equation.find('/');
+            int mid = equation.find('/');
-        int start = equation.rfind(' ', mid - 1);
+            int begin = equation.find(nodes[mid - 1] + nodes[mid]);
-        int end = equation.find(' ', mid + 1);
+            int end = equation.find(nodes[mid] + nodes[mid + 1], begin) + (nodes[mid] + nodes[mid + 1]).length();
-        double a = stod(equation.substr(start + 1, mid - 1));
+            evalStr[eval.front()] = equation.substr(begin, end - begin);
-        double b = stod(equation.substr(mid + 1, end - 1));
+            equation.replace(begin, end - begin, eval);
-        
+            eval.front()++;
-        std::string insert = std::to_string(a / b);
+            idx = end + 1;
-        
-        equation.replace(start, end, insert.c_str());
-
-    }
-    while(equation.find('+') != std::string::npos) {
-        int mid = equation.find('+');
-        int start = equation.rfind(' ', mid - 1);
-        int end = equation.find(' ', mid + 1);
-        double a = stod(equation.substr(start + 1, mid - 1));
-        double b = stod(equation.substr(mid + 1, end - 1));
-        
-        std::string insert = std::to_string(a + b);
-        
-        equation.replace(start, end, insert.c_str());
-
-    }
-    while(equation.find('-') != std::string::npos) {
-        int mid = equation.find('-');
-        int start = equation.rfind(' ', mid - 1);
-        if(start == std::string::npos) {
-            break;
         }
-        int end = equation.find(' ', mid + 1);
-        double a = stod(equation.substr(start + 1, mid - 1));
-        double b = stod(equation.substr(mid + 1, end - 1));
-        
-        std::string insert = std::to_string(a - b);
-        
-        equation.replace(start, end, insert.c_str());
-
     }
-
+    idx = 0;
-    return equation;
+    index(equation, nodes);
+    // + or -
+    while(equation.find('+', idx) != std::string::npos || equation.find('-', idx) != std::string::npos) {
+        if(equation.find('+', idx) < equation.find('-', idx) && equation.find('+', idx) != std::string::npos) {
+            int mid = equation.find('+');
+            int begin = equation.find(nodes[mid - 1] + nodes[mid]);
+            int end = equation.find(nodes[mid] + nodes[mid + 1], begin) + (nodes[mid] + nodes[mid + 1]).length();
+            evalStr[eval.front()] = equation.substr(begin, end - begin);
+            equation.replace(begin, end - begin, eval);
+            eval.front()++;
+            idx = end + 1;
+        } else if(equation.find('-', idx) != std::string::npos) {
+            int mid = equation.find('-');
+            int begin = mid;
+            if(nodes.find(mid - 1) != nodes.end()) {
+                begin = equation.find(nodes[mid - 1] + nodes[mid]);
+            }
+            int end = equation.find(nodes[mid] + nodes[mid + 1], begin) + (nodes[mid] + nodes[mid + 1]).length();
+            evalStr[eval.front()] = equation.substr(begin, end - begin);
+            equation.replace(begin, end - begin, eval);
+            eval.front()++;
+            idx = end + 1;
+        }
+    }
+    
+    return std::to_string(evaluate(equation, evalStr));
 }
 
 
@@ -145,8 +254,9 @@ void Calculator::basicCalculator() {
             ImGui::BeginGroup();
             {
                 if(ImGui::Button("AC")) {
-                    s += " + ";
+                    s.clear();
                 }
+                ImGui::SameLine();
                 if(ImGui::Button("()")) {
 
                     if(parenthesis) {
@@ -157,9 +267,11 @@ void Calculator::basicCalculator() {
 
                     parenthesis = !parenthesis;
                 }
+                ImGui::SameLine();
                 if(ImGui::Button("Gr")) {
                     graphing = true;
                 }
+                ImGui::SameLine();
                 if(ImGui::Button("=")) {
                     s = calculate(s);
                 }
@@ -190,15 +302,17 @@ void Calculator::basicCalculator() {
                 }
                 ImGui::SameLine();
                 if(ImGui::Button("del")) {
-                    if(s.back() == ' ') {
+                    if(!s.empty()) {
-                        s.pop_back();
+                        if(s.back() == ' ') {
-                        if(s.back() == '(' || s.back() == ')') {
+                            s.pop_back();
-                            parenthesis = !parenthesis;
+                            if(s.back() == '(' || s.back() == ')') {
+                                parenthesis = !parenthesis;
+                            }
+                            s.pop_back();
+                            s.pop_back();
+                        } else {
+                            s.pop_back();
                         }
-                        s.pop_back();
-                        s.pop_back();
-                    } else {
-                        s.pop_back();
                     }
                 }
             }

modules/Archimedes-Modules/Calculator/Calculator.h

@@ -22,8 +22,11 @@ class Calculator : public Archimedes::Module {
         void basicCalculator();
 
         std::string calculate(std::string);
+        double evaluate(std::string, std::unordered_map<char, std::string>&);
+        void index(std::string, std::unordered_map<unsigned int, std::string>&);
 
         void graphingCalculator();
+
 };
 
 #ifdef CALCULATOR_DYNAMIC