About Lesson
- Write a function to convert hexadecimal digits (including an optional 0x or 0X) into its equivalent integer value. Valid input characters are 0-9 and a-f (or A-F).
- Write a function to convert a string containing digits to integer.
- Write a function concat, which concatenates two strings. The function takes two string arguments and the first argument will have the resulting string.
- Write a function squeeze(s1, s2), which deletes each character in string s1 that matches any character in string s2. You may assume that the input only contains lower case alphabets.
- Write a function that counts the number of non-zero bits in a given non-negative integer.