Initial commit

2019-11-15 12:59:38 +01:00
parent 40a414d210
commit b880c3ccde
6814 changed files with 379441 additions and 0 deletions
@@ -0,0 +1,91 @@
+A four-function postfix calculator.
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cmath>
+using namespace std;
+
+int main()
+{
+  stack<double> stackObject;
+  double a, b;
+  string s;
+
+  do {
+    cout << ": ";
+    cin >> s;
+    switch( s[ 0 ]) {
+      case 'q': // quit the calculator
+        break;
+      case '.': // show top-of-stack
+        cout << stackObject.top() << endl;
+        break;
+      case '+': // add
+        if(stackObject.size() < 2) {
+          cout << "Operand Missing\n";
+          break;
+        }
+
+        a = stackObject.top();
+        stackObject.pop();
+        b = stackObject.top();
+        stackObject.pop();
+        cout << a + b << endl;
+        stackObject.push(a + b);
+        break;
+      case '-': // subtract
+        // see if user entering a negative number
+        if(s.size() != 1) {
+          // push value onto the stack
+          stackObject.push(atof(s.c_str()));        
+          break;
+        }
+
+        // otherwise, is a subtraction
+        if(stackObject.size() < 2) {
+          cout << "Operand Missing\n";
+          break;
+        }
+
+        a = stackObject.top();
+        stackObject.pop();
+        b = stackObject.top();
+        stackObject.pop();
+        cout << b - a << endl;
+        stackObject.push(b - a);
+        break;
+      case '*': // multiply
+        if(stackObject.size() < 2) {
+          cout << "Operand Missing\n";
+          break;
+        }
+
+        a = stackObject.top();
+        stackObject.pop();
+        b = stackObject.top();
+        stackObject.pop();
+        cout << a*b << endl;
+        stackObject.push(a*b);
+        break;
+      case '/': // divide
+        if(stackObject.size() < 2) {
+          cout << "Operand Missing\n";
+          break;
+        }
+
+        a = stackObject.top();
+        stackObject.pop();
+        b = stackObject.top();
+        stackObject.pop();
+        cout << b/a << endl;
+        stackObject.push(b/a);
+        break;
+      default:      
+        // push value onto the stack
+        stackObject.push(atof(s.c_str()));        
+        break;
+    }
+  } while(s != "q");
+
+  return 0;
+}