Programming Example
R Program to Make a Simple Calculator
In this program we will create a simple calculator using R programming language.
In this program we will create a simple calculator using R programming language.
To understand this example, you should have knowledge of following R programming topics:
# Program make a simple calculator that can add, subtract, multiply and divide using functions
add <- function(x, y) {
return(x + y)
}
subtract <- function(x, y) {
return(x - y)
}
multiply <- function(x, y) {
return(x * y)
}
divide <- function(x, y) {
return(x / y)
}
# take input from the user
print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")
choice = as.integer(readline(prompt="Enter choice[1/2/3/4]: "))
num1 = as.integer(readline(prompt="Enter first number: "))
num2 = as.integer(readline(prompt="Enter second number: "))
operator <- switch(choice,"+","-","*","/")
result <- switch(choice, add(num1, num2), subtract(num1, num2), multiply(num1, num2), divide(num1, num2))
print(paste(num1, operator, num2, "=", result))<pre><samp>[1] "Select operation."
[1] "1.Add"
[1] "2.Subtract"
[1] "3.Multiply"
[1] "4.Divide"
Enter choice[1/2/3/4]: 4
Enter first number: 20
Enter second number: 4
[1] "20 / 4 = 5"</samp></pre>
In this program, we ask the user to choose the desired operation. Options 1, 2, 3 and 4 are valid.
Two numbers are taken from the user and a switch branching is used to execute a particular function.
User-defined functions add(), subtract(), multiply() and divide() evaluate respective operations.
First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.
After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.