Question

Using the windows32 framework, write a procedure to read a string and
shift each character of the string by one. As an example, if your input string is Abcz,
your output should be Bcda. Note that you must test your string for non-alphabetic
characters (such as numbers and special characters). If there are non-alphabetic characters, you should terminate your program with an appropriate message. You should
display your converted string using the output macro.
Hint: Let your procedure returns an empty string, if the parameter is not valid. Then
depending on the return value, print an appropriate message in your main procedure.

Using Assembly language windows 32 framework

Answer 1

Given a string S of only small English letters. We need to transform the string by making some number of moves (any number of times) to get the string “abcdefghijklmnopqrstuvwxyz” as a subsequence in that string. In one move, you can replace any character of the string to next character in alphabetical order i.e. ‘a’ can be replaced by ‘b’, ‘b’ can be replaced by ‘c’ and so on. Letter ‘z’ cannot be replaced by any character. If it is not possible to get the subsequence out of that string, then print “Not Possible”.

Examples:

Input : aaaaaaaaaaaaaaaaaaaaaaaaaa
Output : abcdefghijklmnopqrstuvwxyz
Explanation: Second occurrence of letter 'a' will be 
replaced by 'b', third occurrence of letter 'a' will 
be first replaced by 'b' and then by 'c' and so on.

using namespace std;

// function to transform string with string

// passed as reference

bool transformString(string& s)

{

    // initializing the variable ch to 'a'

    char ch = 'a';

    // if the length of string is less than

    // 26, we can't obtain the required

    // subsequence

    if (s.size() < 26)

        return false;    

    for (int i = 0; i < s.size(); i++) {

        // if ch has reached 'z', it means we have

        // transformed our string such that required

        // subsequence can be obtained

        if (int(ch) > int('z'))

            break;

        // current character is not greater than ch,

        // then replace it with ch and increment ch

        if (s[i] <= ch) {

            s[i] = ch;

            ch = char(int(ch) + 1);

        }

    }

     

    if (ch <= 'z')

        return false;

    return true;

}

// Driver Code

int main()

{

    string str = "aaaaaaaaaaaaaaaaaaaaaaaaaa";    

    if (transformString(str))

        cout << str << endl;

    else

        cout << "Not Possible" << endl;

    return 0;

}