Sample Programs Using Conditional and Iterative Statements in R

 

Sample Programs Using Conditional and Iterative Statements in R

These programs illustrate the use of if, if-else, if-else-if, for, while, repeat, break, and next statements.

---

1. Check Whether a Number is Positive, Negative, or Zero

Program

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

if(num > 0)
{
    print("Positive Number")
}else if(num < 0)
{
    print("Negative Number")
}else
{
    print("Zero")
}

Sample Output

Enter a number: -5
[1] "Negative Number"

---

2. Check Whether a Number is Even or Odd

Program

num <- as.integer(readline("Enter a number: "))

if(num %% 2 == 0)
{
    print("Even Number")
}
else
{
    print("Odd Number")
}

---

3. Find the Largest of Three Numbers

Program

a <- 15
b <- 30
c <- 25

if(a > b & a > c)
{
    largest <- a
}else if(b > c)
{
    largest <- b
}else
{
    largest <- c
}

cat("Largest Number =", largest)

Output

Largest Number = 30

---

4. Grade Calculation Using if-else-if

Program

marks <- as.numeric(readline("Enter marks: "))

if(marks >= 90)
{
    grade <- "A"
}else if(marks >= 75)
{
    grade <- "B"
}else if(marks >= 60)
{
    grade <- "C"
}else
{
    grade <- "F"
}

cat("Grade =", grade)

---

5. Multiplication Table Using for Loop

Program

n <- as.integer(readline("Enter a number: "))

for(i in 1:10)
{
    cat(n, "x", i, "=", n*i, "\n")
}

Sample Output

5 x 1 = 5
5 x 2 = 10
...
5 x 10 = 50

---

6. Sum of digits of a Number Using while Loop

Program

n <- as.integer(readline("Enter n: "))

i <- 1
sum <- 0

while(n !=0)
{
  sum <- sum + n%%10
  n <- n%/%10
}

cat("Sum =", sum)

Output

Enter n: 125
Sum = 8

---

7. Factorial of a Number Using repeat Loop

Program

n <- 5
fact <- 1
i <- 1

repeat
{
    fact <- fact * i
    i <- i + 1

    if(i > n)
        break
}

cat("Factorial =", fact)

Output

Factorial = 120

---

8. Demonstration of break Statement

Program

for(i in 1:10)
{
    if(i == 6)
        break

    print(i)
}

Output

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5

The loop terminates when i becomes 6.

---

9. Demonstration of next Statement

Program

for(i in 1:10)
{
    if(i %% 2 == 0)
        next

    print(i)
}

Output

[1] 1
[1] 3
[1] 5
[1] 7
[1] 9

The even numbers are skipped.

---

10. Prime Number Check

Program

num <- as.integer(readline("Enter a number: "))

flag <- TRUE

if(num <= 1)
{
  flag <- FALSE
}else
{
  for(i in 2:floor(sqrt(num)))
  {
    if(num %% i == 0)
    {
      flag <- FALSE
      break
    }
  }
}

if(flag)
{
  print("Prime Number")
  
  
}else
{
  print("Not a Prime Number")
}

Output

Enter a number: 13

[1] "Prime Number"