/* A Simple Calculator By Giancarlo Forero A really basic calculator in C++. Sadly, SoloLearn doesn't accept input very well so it doesn't work as well as it should. I had to comment out the while loop which allows you to continue using the calculator infinitely. If you want the best version of this calculator, head to this url: https://repl.it/@gforero_tuts/Calculator ALSO: Sorry about strange indentation in certain places, I didn't originally write this here in the SoloLearn Code Playground. UPDATE: Working on a new calculator which is much more advanced and accepts equations such as 5 + 5 - 3 * 5. Sadly this new calculator most likely won't be able to detect parenthesis due to the difficulties this causes. */ /* Calculator Inputs First asks for input which can be: - ans Previous Answer (Doesn't work if this the first input) - double A Double - pi Pi Next asks for the operator which can be: - + Addition - - Subtraction - / Division - * Multiplication Finally asks for the final input which can be the same as the first input EXAMPLE INPUT: 2 + 2 */ #include #include #include using namespace std; // Output text void out(string str) { cout << str << endl; } void out(int num) { cout << num << endl; } void out(double num) { cout << num << endl; } void out(float num) { cout << num << endl; } void out(char cha) { cout << cha << endl; } // Get input via std::cin string in() { string input; cin >> input; return input; } // Turn a string lowercase string lower(string sStr) { string str = sStr; transform(str.begin(), str.end(), str.begin(), ::tolower); return str; } // Checks to see if a string has a certain lowercase match at the beginning bool isEqualTo(string txt, string matc) { if (lower(txt.substr(0,matc.length())) == lower(matc)) { return true; } else { return false; } } int main() { // Holds first input, second input, first double input, second double input, result, and operator string fFI, sFI; double fI, sI, result; char oper; // Holds pi and the previous answer double previousAnswer = 0; const double pi = 3.14159265359; // Send a list of valid inputs out("Valid Inputs:"); out("- pi\t\tPI"); out("- ans or answer\tPREVIOUS ANSWER"); out("- number\tANY NUMBER"); out(""); // Get input out("Input #1"); fFI = in(); // Get fFI (first string input) out("Input an operator (+, -, /, *)"); oper = *in().substr(0,1).c_str(); // Get operator character (first character in string) out("Input #2"); sFI = in(); // Get sFI (second string input) // Check the first input to see if it uses special keywords if (isEqualTo(fFI, "ans") || isEqualTo(fFI, "answer")) { fI = previousAnswer; } else if (isEqualTo(fFI, "pi")) { fI = pi; } else { fI = atof(fFI.c_str()); } // Check the second input to see if it uses special keywords if (isEqualTo(sFI, "ans") || isEqualTo(sFI, "answer")) { sI = previousAnswer; } else if (isEqualTo(sFI, "pi")) { sI = pi; } else { sI = atof(sFI.c_str()); } // Perform the operation based on the operator given switch (oper) { case '+': previousAnswer = fI + sI; break; case '-': previousAnswer = fI - sI; break; case '/': previousAnswer = fI / sI; break; case '*': previousAnswer = fI * sI; break; default: cout << "UNKNOWN OPERATOR" << endl; } out(""); // Output the result and the operation performed out("Operation Performed:"); cout << fI << " " << oper << " " << sI << endl; cout << "Result: " << previousAnswer << endl; out("\n\n\n"); }

Calculator - Broken