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Given a positive integer N[at least contain two digits]. The task is to write a Python program to add the first and last digit of the given number N.
Examples:
Input: N = 1247 Output: 8 Explanation: First digit is 1 and Last digit is 7. So, addition of these two [1 + 7] is equal to 8.
Input: N = 73 Output: 10
Method 1: String implementation
- Take input in the form of String or typecast given input in String.
- Now pick the 0th index of the String and typecast it into Integer and store it in a variable.
- The same thing with the -1st index and also store in another variable.
- Now add these two variables and
- print them as an Output.
Note: We can access the first element of String using string[0] and the last element of String using string[-1].
String Representation
Python3
number
=
1247
number
=
str
[number]
first_digit
=
int
[number[
0
]]
last_digit
=
int
[number[
-
1
]]
addition
=
first_digit
+
last_digit
print
[
'Addition of first and last digit of the number is'
,
addition]
Output:
Addition of first and last digit of the number is 8
Time complexity: O[1] since performing constant operations
Auxiliary Space: O[1] since using constant space for variables
Method 2: Solve it using an integer
- We have given a positive Integer.
- After dividing by 10, store the remainder in a result variable.
- Continue the loop until the number becomes less than 9.
- Each time in the loop, divide the number by 10[integer division].
- After the end of the loop.
- Add the number in the result variable.
- Display the result variable as the output.
Note: Whenever we divide any number with 10, we get the last digit as the remainder. If we divide any number with 100, we get the last two-digit as the remainder.
Python3
number
=
1247
res
=
number
%
10
while
number >
9
:
number
=
number
/
/
10
res
+
=
number
print
[
'Addition of first and last digit of number is'
, res]
Output:
Addition of first and last digit of the number is 8
Time Complexity: O[n], where n is how many digits are there in the given number.
Auxiliary Space: O[1] since using constant space for variables
Python program to get an number n from user and display the last digit of n
Sample Input 1:
623
Sample Output 1:
3
Sample Input 2:
280
Sample Output 2:
0
Program or Solution
num=int[input["enter the number:"]]
ldigit=num%10
print["last digit: {}".format[ldigit]]
Program Explanation
Get a number num [using input[] method] Seprate the last digit of number num by "digit = num%10".
[% by 10 always gives last digit of a number] print the digit [using print[] method]
In this program, we first read This Python program calculates sum of first and last digit of a given number.
number
from user. Then we reverse it using [::-1]
. After reversing, we convert both number
& reverse
to integer using int[]
function. first_digit
is obtained by reverse%10
and last_digit
is obtained by number%10
. Finally we calculate sum of first & last digit to get final result.Python Source Code: Sum of First & Last Digit
# Sum of first & last digit
# Reading number
number = input["Enter number: "]
# Reversing number
reverse = number[::-1]
# Converting number and its reverse to integer
number = int[number]
reverse = int[reverse]
# Finding first digit
first_digit = reverse % 10
# Finding last digit
last_digit = number % 10
# Finding sum
total_sum = first_digit + last_digit
# Displaying sum
print["Sum of first & last digit of %d is %d" %[number, total_sum]]
Output
Enter number: 99975
Sum of first & last digit of 99975 is 14