Reversing a string in C means rearranging its characters so the last character becomes the first and vice versa: “Hello” becomes “olleH”. The standard technique is the two-pointer swap — place one pointer at the start and one at the end, swap the characters they point to, then move the pointers toward each other until …
Exercise 1-19. Write a function reverse(s) that reverses the character string s. Use it to write a program that reverses its input a line at a time. Approach The core algorithm is the classic two-pointer swap: place one index at the start of the string (i = 0) and one at the end (j = …
A palindrome is a word, sentence, or sequence that reads the same forward and backward — ignoring differences in capitalization for word-level palindromes. Examples: “racecar”, “GADAG”, “level”, “9009”. The most efficient check uses a two-pointer approach: one pointer starts at the left end, one at the right, and they advance toward each other until they …