Page 273 - Computer Science Class 11 Without Functions
P. 273
11.6.4 Constructing the Reverse of a Given String
Let us develop a program that takes a string as an input from the user.
● Next, we initialize the string comprising characters in reverse order (revString) to an empty string (line 9).
● Next, we scan the string and append every subsequent letter to the beginning of the revString (lines 11-12).
● Finally, output the reversed string (revString) (line 14).
Program 11.4 Constructing the reverse of a string
01 '''
02 Objective: To reverse the given string
03 Input: string - string value
04 Output: string with the characters of the string reversed
05 '''
06
07 string = input('Enter a string: ')
08
09 revString = ''
10 lengthSubstr = len(string)
11 for char in string:
12 revString = char + revString
13
14 print('Reverse of ', string, ' is:',revString)
Solved Programming Question
A string is a palindrome if it reads the same from both ends, for example, 'madam', 'rotator', 'level',
'abcde0edcba'. Write a program to check whether a given string is a palindrome. The program takes a
string as input from a user and makes prints an appropriate message depending on whether the input string is a
palindrome.
Ans. Objective: To check whether the given string is a palindrome.
Input: string – a Python string
Output: Appropriate message when string is a palindrome and when it is not.
'''
'''
Approach:
For each position i in string, check if elements at i and len(string)-(i-1) th locations
are the same.
If this holds true for all i in range [1, len(string)/2] return True else False.
'''
myString = input('Enter a string to check:')
n = len(myString)
flag = True
if n == 0: #null string
flag = True
else:
j = n-1 #index of the rightmost character
for i in range(n//2+1):
if myString[i] != myString[j]:
flag = False #character mismatch
j -= 1
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