Write a program that reads in a line consisting of a student’s name, Social Security number, user ID, and password. The program outputs the string in which all the digits of the Social Security number and all the characters in the password are replaced by x. (The Social Security number is in the form 000-00-0000, and the user ID and the password do not contain any spaces.) Your program should not use the operator [] to access a string element. Use the appropriate functions described in Table 7-1 below. Expression Effect strVar.at(index) Returns the element at the position specified by index strVar[index] Returns the element at the position specified by index strVar.append(n, ch) Appends n copies of ch to strVar, where ch is a char variable or a char constant strVar.append(str) Appends str to strVar strVar.clear() Deletes all the characters in strVar strVar.compare(str) Returns 1 if strVar > str returns 0 if strVar == str; returns −1 if strVar < str strVar.empty() Returns true if strVar is empty; otherwise it returns false strVar.erase() Deletes all the characters in strVar strVar.erase(pos, n) Deletes n characters from strVar starting at position pos strVar.find(str) Returns the index of the first occurrence of str in strVar. If str is not found, the special value string::npos is returned strVar.find(str, pos) Returns the index of the first occurrence at or after pos where str is found in strVar strVar.find_first_of(str, pos) Returns the index of the first occurrence of any character of strVar in str. The search starts at pos strVar.find_first_not_of(str, pos) Returns the index of the first occurrence of any character of str not in strVar. The search starts at pos strVar.insert(pos, n, ch) Inserts n occurrences of the character ch at index pos into strVar; pos and n are of type string::size_type; and ch is a character strVar.insert(pos, str) Inserts all the characters of str at index pos into strVar strVar.length() Returns a value of type string::size_type giving the number of characters in strVar strVar.replace(pos, n, str) Starting at index pos, replaces the next n characters of strVar with all the characters of str. If n > length of strVar, then all the characters until the end of strVar are replaced strVar.substr(pos, len) Returns a string which is a substring of strVar starting at pos. The length of the substring is at most len characters. If len is too large, it means “to the end“ of the string in *strVar strVar.size() Returns a value of type string::size_type giving the number of characters in strVar strVar.swap(str1) Swaps the contents of strVar and str1. str1 is a string variable