*** USING C++ *** Topics Methods Description Write a program that will implement
ID: 3838451 • Letter: #
Question
*** USING C++ ***
Topics
Methods
Description
Write a program that will implement a simple calculator. The program will prompt the user to input an operation and two decimal numbers. It will perform the specified operation on the two decimal numbers and will display the result. The program will allow the following values for operation:
+ (means add)
- (means subtract)
* (means multiply)
/ (means divide)
The program will do the above repeatedly so that a user may perform different operations on a different pair of numbers.
/* C++ users
The program will end when the user enters x for operation.
*/
Testing
Test Run
Enter an operation
+
Enter the first number
2.2
Enter the second number
1.1
The result is 3.3
Enter an operation
-
Enter the first number
2.2
Enter the second number
1.1
The result is 1.1
Enter an operation
*
Enter the first number
2.2
Enter the second number
1.1
The result is 2.42
Enter an operation
/
Enter the first number
2.2
Enter the second number
1.1
The result is 2
Enter an operation
press cancel (java users)
x (c++ users)
Implementation
The program will provide two methods: main and calculate.
Method calculate
The method calculate will receive three parameters and will return a double value.
It will receive the following three parameters.
A char parameter op for receiving the operation value. The possible values for this parameter are: +, -, *, /.
A double parameter n1 for receiving the first operand.
A double parameter n2 for receiving the second operand.
It will return a double value.
Below is the sample method header with an empty body.
C++ Users
*/
double calculate (String op, double n1, double n2)
{
}
Method main ( )
The method main will do the following repeatedly:
· It will prompt the user to enter the desired operation.
· It will prompt the user to enter the first operand.
· It will prompt the user to enter the second operand.
· It will call the method calculate and pass it the operation and the two operands as parameters.
· On return from calculate, the method main will receive the result in a variable using an assignment statement.
· It will display the result.
Explanation / Answer
#include <iostream>
using namespace std;
double calculate (string op, double n1, double n2)
{
if(op=="+"){
return n1+n2;
}
else if(op=="-"){
return n1-n2;
}
else if(op=="*"){
return n1* n2;
}
else if(op=="/") {
return n1/n2;
}
return -1;
}
int main()
{
string op;
double n1,n2,result;
while(true) {
cout << "Enter an operation: " ;
cin >> op;
if(op=="x"){
break;
}
cout <<"Enter the first number: " ;
cin >> n1;
cout << "Enter the second number: " ;
cin >> n2;
result = calculate(op,n1,n2);
if(result!=-1)
cout<<"The result is "<<result<<endl;
else
cout<<"The operation is invalid."<<endl;
}
cout<<"Bye"<<endl;
return 0;
}
Output:
sh-4.2$ g++ -o main *.cpp
sh-4.2$ main
Enter an operation: +
Enter the first number: 2.2
Enter the second number: 1.1
The result is 3.3
Enter an operation: -
Enter the first number: 2.2
Enter the second number: 1.1
The result is 1.1
Enter an operation: x
Bye
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