Problem 1
Fill in the blanks in each of the following: a. Header ___________ must be included for class string. b. Class string belongs to the ______________ namespace. c. Function ___________ deletes characters from a string. d. Function ___________ finds the first occurrence of any character from a string.
Problem 3
Find the error(s) in each of the following, and explain how to correct it (them): a. string string1( 28 ); // construct string1 string string2( 'z' ); // construct string2 b. // assume std namespace is known const char *ptr = name.data(); // name is "joe bob" ptr[ 3 ] = '-'; cout << ptr << endl;
Problem 6
Find any errors in the following and explain how to correct them: a. std::cout << s.data() << std::endl; // s is "hello" b. erase( s.rfind( "x" ), 1 ); // s is "xenon" c. string& foo() { string s( "Hello" ); ... // other statements return; } // end function foo
Problem 7
( simple Encryption) Some information on the Internet may be encrypted with a simple algorithm known as "rot13," which rotates each character by 13 positions in the alphabet. Thus, 'a' corresponds to 'n', and 'x' corresponds to 'k'. rot13 is an example of symmetric key encryption. With symmetric key encryption, both the encrypter and decrypter use the same key. a. Write a program that encrypts a message using rot13. b. Write a program that decrypts the scrambled message using 13 as the key. c. After writing the programs of part (a) and part (b), briefly answer the following question: If you did not know the key for part (b), how difficult do you think it would be to break the code? What if you had access to substantial computing power (e.g., supercomputers)? In Exercise 18.26 we ask you to write a program to accomplish this.
Problem 9
Write a program that reads in several strings and prints only those ending in "r" or "ay". Only lowercase letters should be considered.
Problem 11
Write a program that separately inputs a first name and a last name and concatenates the two into a new string.
Problem 12
Write a program that plays the game of Hangman. The program should pick a word (which is either coded directly into the program or read from a text file) and display the following: Guess the word: XXXXXX Each X represents a letter. The user tries to guess the letters in the word. The appropriate response yes or no should be displayed after each guess. After each incorrect guess, display the diagram with another body part filled. After seven incorrect guesses, the user should be hanged. The display should look as follows: O /|\ | / \ After each guess, display all user guesses. If the user guesses the word correctly, the program should display Congratulations!!! You guessed my word. Play again? yes/no
Problem 13
Write a program that inputs a string and prints the string backward. Convert all uppercase characters to lowercase and all lowercase characters to uppercase.
Problem 14
Write a program that uses the comparison capabilities introduced in this chapter to alphabetize a series of animal names. Only uppercase letters should be used for the comparisons.
Problem 17
Write a program that inputs a sentence and counts the number of palindromes in it. A palindrome is a word that reads the same backward and forward. For example, "TRee" is not a palindrome, but "noon" is.
