C++ Example - Implement a simple calculator
Create a simple calculator using C++ that can implement +, -, *, /.
Example
#include <iostream>
using namespace std;
int main()
{
char op;
float num1, num2;
cout << "Input operator: +, -, *, / :";
cin >> op;
cout << "Enter two numbers:";
cin >> num1 >> num2;
switch(op)
{
case '+':
cout << num1+num2;
break;
case '-':
cout << num1-num2;
break;
case '*':
cout << num1*num2;
break;
case '/':
if (num2 == 0)
{
cout << "Error: cannot divide by zero.";
break;
}
else
{
cout << num1 / num2;
break;
}
default:
//If the operator is not +, -, *, or /, display an error message.
cout << "Error! Please enter a valid operator.";
break;
}
return 0;
}
The output of the above program execution is:
输入运算符：+、-、*、/ : + 输入两个数: 1 2 3
Example 2
#include <iostream>
using namespace std;
double add(double num1, double num2) {
return num1 + num2;
}
double subtract(double num1, double num2) {
return num1 - num2;
}
double multiply(double num1, double num2) {
return num1 * num2;
}
double divide(double num1, double num2) {
if (num2 != 0) {
return num1 / num2;
} else {
cout << "Error: The divisor cannot be zero!" << endl;
return 0;
}
}
int main() {
double num1, num2;
char op;
cout << "Please enter the first number:";
cin >> num1;
cout << "Please enter an operator (+, -, *, /):";
cin >> op;
cout << "Please enter the second number:";
cin >> num2;
double result;
switch (op) {
case '+':
result = add(num1, num2);
break;
case '-':
result = subtract(num1, num2);
break;
case '*':
result = multiply(num1, num2);
break;
case '/':
result = divide(num1, num2);
break;
default:
cout << "Error: Invalid operator!" << endl;
return 0;
}
cout << "Results:" << result << endl;
return 0;
}
The output of the above program execution is:
请输入第一个数字：4 请输入运算符（+、-、*、/）：/ 请输入第二个数字：2 结果：2other extensions