How to make a calculator ? Pls post the program

Answer 1

well try one of these two codes :

code 1
---------------

#include <iostream>
using namespace std;

//Function prototype
int solve(int, int, char);

int main()
{
//Declare variables
int solution, num1, num2;
char oper;

//Output
cout << "Calculator\n----------\n" << endl;
cout << "Syntax:\n" << endl;
cout << "1 + 3\n" << endl;
cout << "Operators: +, -, *, /\n" << endl;
cout << "Equation: ";

//Input
cin >> num1 >> oper >> num2;

//Solve and output
solution = solve(num1, num2, oper);
cout << "Answer: " << solution << endl;

//Pause [until enter key] and exit
cin.ignore(); //Enter key from last cin may be passed, ignore it.
cin.get();
return 0;
}

int solve(int num1, int num2, char oper)
{
//Switch oper
switch(oper)
{
case '+':
return num1 + num2;
case '-':
return num1 - num2;
case '*':
return num1 * num2;
case '/':
return num1 / num2;
default:
cout << "\nIncorrect operation! Try again: ";
cin >> num1 >> oper >> num2;
solve(num1, num2, oper);
}
}

code 2
-----------

To understand this example, you should have the knowledge of following C++ programming topics:

C++ switch..case Statement
C++ break and continue Statement

This program takes an arithmetic operator (+, -, *, /) and two operands from an user and performs the operation on those two operands depending upon the operator entered by user.

# include <iostream>
using namespace std;

int main()
{
char op;
float num1, num2;

cout << "Enter operator either + or - or * or /: ";
cin >> op;

cout << "Enter two operands: ";
cin >> num1 >> num2;

switch(op)
{
case '+':
cout << num1+num2;
break;

case '-':
cout << num1-num2;
break;

case '*':
cout << num1*num2;
break;

case '/':
cout << num1/num2;
break;

default:
// I

Answer 2

# include <iostream>
using namespace std;

int main() {

char op;
float num1, num2;

cout << "Enter operator: +, -, *, /: ";
cin >> op;

cout << "Enter two operands: ";
cin >> num1 >> num2;

switch(op) {

case '+':
cout << num1 << " + " << num2 << " = " << num1 + num2;
break;

case '-':
cout << num1 << " - " << num2 << " = " << num1 - num2;
break;

case '*':
cout << num1 << " * " << num2 << " = " << num1 * num2;
break;

case '/':
cout << num1 << " / " << num2 << " = " << num1 / num2;
break;

default:
// If the operator is other than +, -, * or /, error message is shown
cout << "Error! operator is not correct";
break;
}

return 0;
}
Run Code
Output

Enter operator: +, -, *, /: -
Enter two operands: 3.4 8.4
3.4 - 8.4 = -5

Thi