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 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
