Start Programming in R

📘 Introduction to R Programming – Basics with Examples

📌 1. Basic Syntax

• Case sensitive.
• Comments start with #

# This is a comment
print("Hello, R!")

🔢 2. Operators

🔸 Arithmetic

2 + 3    # 5
4 * 5    # 20
6 %% 4   # 2
5 ^ 2    # 25

🔸 Relational

4 == 4   # TRUE
5 != 3   # TRUE
3 < 2    # FALSE

🔸 Logical

TRUE & FALSE   # FALSE
TRUE | FALSE   # TRUE
!TRUE          # FALSE

🔤 3. Data Types

• Numeric: x <- 45.5
• Integer: x <- 100L
• Character: x <- "Hello"
• Logical: x <- TRUE

x <- 42
print(class(x))  # "numeric"

📦 4. Variable Declaration

name <- "R Language"
age <- 25
_height <- 170

🔐 5. Constants

Use uppercase by convention. R doesn't enforce constant rules.

PI <- 3.14159
MAX_USERS <- 100

📥 6. Input

name <- readline("Enter your name: ")
num <- as.numeric(readline("Enter a number: "))

📤 7. Output

x <- 10
print(x)
cat("Value is", x)

✅ Solved Examples

Example 1: Add Two Numbers

a <- as.numeric(readline("Enter first number: "))
b <- as.numeric(readline("Enter second number: "))
sum <- a + b
cat("Sum is", sum)

Example 2: Check Even or Odd

num <- as.integer(readline("Enter a number: "))
if (num %% 2 == 0) {
  print("Even")
} else {
  print("Odd")
}

❓ Unsolved Practice

• Swap two numbers without using a third variable.
• Calculate the square root of a number.
• Compare two numbers and print the greater one.
• Take name and age input, then display a greeting.
• Calculate area of circle using radius and constant PI.