Elaborate the symbols of abstract data type

length(a)-returns the number of characters in symbol a.

capitalize(a)-returns the symbol generated from a by making its first character uppercase and making its remaining characters lowercase.

downcase(a) -returns the symbol generated from a by making all characters in a lowercase.

upcase(a)-returns the symbol generated from a by making all characters in a uppercase.

swapcase(a)-returns the symbol generated from a by making all lowercase characters in a uppercase and all uppercase characters in a lowercase.

charAt(a,i)-returns the one character symbol consisting of the character of symbol a at index i (counting from 0); the result is undefined if  i is less than 0 or greater than or equal to the length of a., ignoring case, and returns -1 if a

length(a)-returns the number of characters in symbol a.

capitalize(a)-returns the symbol generated from a by making its first character uppercase and making its remaining characters lowercase.

downcase(a) -returns the symbol generated from a by making all characters in a lowercase.

upcase(a)-returns the symbol generated from a by making all characters in a uppercase.

swapcase(a)-returns the symbol generated from a by making all lowercase characters in a uppercase and all uppercase characters in a lowercase.

charAt(a,i)-returns the one character symbol consisting of the character of symbol a at index i (counting from 0); the result is undefined if  i is less than 0 or greater than or equal to the length of a.

charAt(a,i,c)-returns substring of symbol a beginning at index i (counting from 0), and continuing for c characters; result is undefined if i is less than 0 or greater than or equal to length of a, or if c is negative. If i+c is greater than the length of a, result is the suffix of symbol a beginning at index i.

succ(a)-returns the symbol which is the successor of symbol a. If a comprise characters or letters, successor of  a is found by incrementing the right-most letter or digit according to the Unicode collating sequence, carrying leftward if required when last digit or letter in collating sequence is encountered. If a has no letters or digits, then right-most character of a is incremented, with carries to the left as necessary.

toString(a)-returns a string whose characters correspond to the characters of symbol a.

toSymbol(a)-returns a symbol whose characters correspond to the characters of string a.