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Homework Help: C++ arrary help thx

  1. Apr 2, 2010 #1
    I am having trouble trying to get my code to run for the following:
    // Use substitution strings to replace all the occurrences
    // of multiple tags in the lines of text in a form.
    // The user enters the filename.
    // The tags and their substitution strings are found in another file.
    // The user enters the filename.
    // Output the result to the file letter.txt.
    // The counts of substitutions for each tag will be output to the screen
    // sorted alphabetically by tag names.

    #include <iostream>
    #include <iomanip>
    #include <fstream>
    #include <string>

    using namespace std; //introduces namespace std

    // Maximum nunber of tagged fields
    const int MAXFIELDS = 20;

    // Structure to hold the tag and substitution string.
    // It is also able to maintain a count of the occurrences of that tag.
    struct Field
    {
    string tag;
    string sub;
    int count;
    };

    // Function declarations
    // Add additional declarations as needed
    int readFields(Field fields[]);
    void trim(string& s);
    string fillForm(const string& form, Field fields[], int nFields);
    string replaceTag(const string& form, Field& field);

    int main( void )
    {
    // Declare string for the form letter

    // Call Function 1 to read in the form letter to the string


    // Declare an array of Fields named fields
    Field fieldsArray[MAXFIELDS];

    // Declare variable for the field count
    // Call Function 2 to read the fields and return the count.


    // Declare string for the finished letter.
    // Call Function 5 that substitutes all the sub strings for the tags.
    // It returns the finished letter.


    // Open the file for the finished letter and test the file stream


    // Write the finished letter to the file


    // Close the file stream


    // Call Function 7 to output the field statistics

    return 0;
    }

    // Function #1
    // This is a function to read a form into a string reference parameter.
    // Write it. Use string concatenation to merge the lines that you read into
    // a single string. Don't forget to insert newline characters.
    // This is nearly the same as the corresponding function in Assignment 6.
    // However, you will now prompt the user to enter the name of the file to open.


    // Function #2
    // This function populates the Fields in an array and returns the count.
    // It is nearly the same as readTagSub() from Assignment 6.
    // Prompt the user for a filename to open.
    // It calls the function to convert the tags to lowercase,
    // and calls the trim function to remove leading whitespace from the
    // substitution string.
    // Observe the use of the subscript and dot operators to access data
    // members of structs in an array.
    int readFields(Field fields[])
    {
    // Declare and initialize count of the fields read
    int n=0;

    // Prompt and read filename.
    // Open the input file and test it.


    // Loop as long as we have not reached the EOF or exceeded the array limit

    {
    // Input the tag

    // Break if there was no tag

    // Call Function 3 to make the tag lowercase

    // Read the rest of the line into the substitution string

    // Call the Function 4 to strip off the leading whitespace characters

    // Set the occurrence count to 0

    // Increment the field count

    }

    // Close the stream

    // Return the field count
    return n;
    }

    // Function #3
    // This function converts the const string reference parameter to
    // all lowercase and returns it.
    // This is exactly the same as the corresponding function in Assignment 6.


    // Function #4
    // This function trims off leading whitespace from the string reference parameter.
    // This is exactly the same as the corresponding function in Assignment 6.
    // Find the position of the first non-whitespace character and use the substr function.
    void trim(string& s)
    {
    // Loop over each leading character until you find one that is not a whitespace.

    // Use substr to assign a new value to s.

    }

    // Function #5
    // This function takes an entire form and returns the string
    // that has all tags replaced with their substitution string.
    string fillForm(const string& form, Field fields[], int nFields)
    {
    // Declare a string variable initialized with the form parameter


    // Loop over all the fields

    {
    // Call Function 6 using the local variable and a single Field.
    // Use the result to update the local string variable.

    }

    // Return the filled form (not "")
    return "";
    }

    // Function #6
    // This function replaces all the occurrences of a single tag
    // with its substitution string. Tags are case-insensitive.
    // This is nearly the same as the corresponding function in Assignment 6.
    // However, it now counts the number of replacements of the tag.
    // Use the dot operator to access the data members of the Field.
    // It returns the new string with this tag's replacements.
    string replaceTag(const string& form, Field& field)
    {
    // Declare a string for the new string
    string newStr;
    // Make a lowercase version of the form to search for the tag

    // Declare instances of size_t for the tag length,
    // start position for the searching, and position of the next tag.
    // Initialize them appropriately.


    // Loop as long as you haven't reached the end of the form

    {
    // Find the position of the next tag in the lowercase version of the form.
    // Use the version of the find function that takes the start position of
    // the search as the second argument.

    // If a tag was found (use string::npos)

    {
    // Concatenate onto the revision the substring from the original form
    // beginning at the start position up to the position of the next tag.

    // Concatenate onto the revision the substitution string.

    // Increment the occurrence count for the tag.

    // Update the start position to just past the end of the tag.

    }
    // Otherwise (tag was not found)

    {
    // Concatenate onto the revision the substring from the original form
    // beginning at the start position up to the end of the form.

    // Update the start position to the length of the form.

    }
    }

    // Return the revision string
    return newStr;
    }

    // Function #7
    // This function outputs the field statistics to cout.
    // Call Function 8 to sort the fields so that the output
    // appears alphabetically by tag name.
    // Write the function definition.


    // Function #8
    // Use either bubble sort or selection sort to sort the
    // array of Field structs alphabetically by tag.
    // There is a similar example of using bubble sort to sort
    // an array of Student structs in the lecture notes.



    // Function #9
    // Swap function for Fields



    I tried many combination of functions and arrays but they wont work. What code goes ater the //
     
  2. jcsd
  3. Apr 3, 2010 #2

    Mark44

    Staff: Mentor

    Well, that's really the question, and is something you need to try. So far, you really don't have much beyond a skeleton of a program. When you get something that will compile, and have some specific questions, let us know.
     
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