Reverse String

Write a function that takes a string as input and reverse the same.

Example:

Given s = "hello", return "olleh".

Approach: The idea is to swap the last and the first characters till the middle is reached.

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string reverseString(string &s) { int low = 0, high = s.length() - 1; while(low < high){ char t = s[low]; s[low] = s[high]; s[high] = t; low++; high--; } return s; }

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Reverse Vowels of a String

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:
Given s = "hello", return "holle".

Approach:  The idea is to traverse the string from both ends while skipping the non-vowels characters from both ends.

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char* reverseVowels(char* s) { int low = 0, high = strlen(s) - 1; char c; while(low < high){ //move forward to skip consonant while(low < strlen(s) && tolower(s[low]) != 'a' && tolower(s[low]) != 'e' && tolower(s[low]) != 'i' && tolower(s[low]) != 'o' && tolower(s[low]) != 'u'){ low++; } //move backward to skip consonant while(low < high && tolower(s[high]) != 'a' && tolower(s[high]) != 'e' && tolower(s[high]) != 'i' && tolower(s[high]) != 'o' && tolower(s[high]) != 'u'){ high--; } if(low < high){ c = s[low]; s[low] = s[high]; s[high] = c; low++; high--; } } return s; }

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