Question

Write a program using c++.

Write a program that uses a loop to keep asking the user for a sentence, and for each sentence tells the user if it is a palindrome or not. The program should keep looping until the user types in END. After that, the program should display a count of how many sentences were typed in and how many palindromes were found. It should then quit.

Your program must have (and use) at least four VALUE RETURNING functions. Start out by writing your own reverse, uppercase and filter functions.

Then write a boolean function that uses the above functions to see if the given string is a palindrome.

• A palindrome checker function that returns true if the passed string is a palindrome or returns false otherwise.

  • • This is a test 123. → false

    • Do geese see god? → true

  • Note, this function should use the previous functions (uppercase, reverse and filter) to do its work

  • A string is a palindrome if it is the same forwards and backwards (once you uppercase it and filter out the non letters and numbers Finally, write a driver function (either in main or in its own function) that has a loop to keep asking the user for strings to check, calls the palindrome checking function and has a counter to count the sentences and palindromes. When the user types END, the program should print out the # of sentences and # of palindromes and quit.

  • Here is an example: Enter a string: Do geese see God?
    Do geese see God? is a palindrome
    Enter a string: This is just junk
    This is just junk is NOT a palindrome
    Enter a string: Murder for a jar of red rum.
    Murder for a jar of red rum. is a palindrome
    Enter a string: Some men interpret nine memos.
    Some men interpret nine memos. is a palindrome
    Enter a string: Never odd or even.
    Never odd or even. is a palindrome
    Enter a string: 1111111
    1111111 is a palindrome
    Enter a string: END

This is what I have so far:

#include <iostream>
using namespace std;

string filter(string s){
string r = ""; // nothing between quotes
//string s = "B Cooper 123 # $ . ! 456";
unsigned int i =0;
while (i < s.length()){
char c = s[i];
if (isalnum(c)) // alphabet or number
r += c;
i++;
}
return r; // BCooper123456
}

//Next is uppercase function

string uppercase(string s){
string r = ""; // nothing between quotes
//string s = "B Cooper 123";
for(unsigned int i =0; i < s.length(); i++){
char c = s[i];
r += toupper(c);
}
return r; // B COOPER 123
}

// Next is the reverse

string reverse(string s){
//string s = "B cooper";
string r = "";
int i =s.length() -1;
while (i >= 0){
r += s[i];
i--;
}
return r;
}

// palindrome checker

bool isPal(string s) {
string fu = filter(uppercase(s));
if ( fu == reverse(fu) )
return true;
else
return false;

}

int main()
{
int palcount = 0;
  
cout << "Enter a sentence." << endl;
getline(cin,s);
  
while (s != "END"){
  
if (isPal(s)){
cout << s << " is a palindrome" << endl;
++palcount;
}
else (isPal(s)){
cout << s << " is NOT a palindrome" << endl;
}
  
cout << "Enter a sentence." << endl;
getline(cin,s);
}
  
cout << "PalCount: " << palcount << endl;
}

Answer 1

Code:

#include <iostream>
#include<string>
using namespace std;

//filter function that takes string as a parameter
//it return a string of only alphabets and numbers
string filter(string s){
   string r = ""; // nothing between quotes
   //string s = "B Cooper 123 # $ . ! 456";
   unsigned int i =0;
  
   //loop until the i less than string length
   while (i < s.length()){
      
       //store character at index i in c
       char c = s[i];
      
       //check if it is alphabet or number
       if (isalnum(c))
          
           //if it is alphabet or number then append it to r
           r += c;
      
       //increment i
       i++;
   }
  
   //return the string that contains alphabets and numbers
   return r; // BCooper123456
}

//Next is uppercase function
//it takse one parameter string
//converts the all letters to uppercase and return it
string uppercase(string s){
  
   string r = ""; // nothing between quotes
   //string s = "B Cooper 123";
  
   //loop until the end of string length
   for(unsigned int i =0; i < s.length(); i++){
      
       //store the character at index i in c
       char c = s[i];
      
       //convert it to uppercase.
       r += toupper(c);
   }
  
   //return the string in upper case
   return r; // B COOPER 123
}

// Next is the reverse

//it takes the one parameter string
//return the reversed string

string reverse(string s){
//string s = "B cooper";
   string r = "";
  
   //store the length of string in i here i be the index value so -1
   int i =s.length() -1;
   while (i >= 0){
      
       //append the last character to the r
       r += s[i];
      
       //decrement i value
       i--;
   }
  
   //return the reversed string
   return r;
}

// palindrome checker
// it takes a string as a parameter
//it return either true or false
bool isPal(string s) {
  
   //call the functions filter and upper
   //pass string s as a paramter
   string fu = filter(uppercase(s));
  
   //check if the fu string and reverse of fu are equal
   //if they are equal they are palindrome return ture
   if ( fu == reverse(fu))
       return true;
      
   //if they are not equal then return false.
   else
       return false;

}

int main()
{
//   declare two variables palcount and sentence_typed
   int palcount = 0,sentence_typed=0;
  
   //declare a string s
   string s;
  
   //read the string from user
   cout << "Enter a string: ";
  
   //read the string
   getline(cin,s);
  
   //increment the sentence_typed value
   sentence_typed++;
  
   //check if the string s if not equal to END
   while (s != "END"){
  
   //   make a function call to isPal pass s as parameter
   //   if it is palindrome then we print palindrome and increment palcount
       if (isPal(s)){
           cout << s << " is a palindrome" << endl<<endl;
           ++palcount;
       }
      
   //   print it is not palindrome
       else{
          
           cout << s << " is NOT a palindrome" << endl<<endl;
       }
      
   //   ask the user to enter next string
       cout << "Enter a string: ";
      
   //   read the string
       getline(cin,s);
      
   //   check if the entered string is not equal to END
   //   then increment the sentence_typed value
       if(s!="END"){
          
           sentence_typed++;
       }
  
   }
  
   //print the sentence typed and palcount
   cout<<endl<<"Sentence Typed : "<<sentence_typed<<endl<<endl;
   cout << "PalCount: " << palcount << endl<<endl;
   return 0;
}