Question

In C++ write a program that will read three strings from the user, a phrase, a letter to replace, and a replacement letter. The program will change the phrase by replacing each occurrence of a letter with a replacement letter. For example, if the phrase is Mississippi and the letter to replace is 's' the new phrase will be "miizzizzippi".

in the function, replace the first parameter is a modifiable string, the second parameter is the occurrence of a letter to be replaced, the third is the replacement letter, and the 4th is an empty and modifiable vector that must contain the new phrase with the replaced letters.

For the function replace, loop through all the characters in the phrase (1st parameter) and use the string function replace to perform each letter replacement where needed. Also, use push_back to insert the letters in the new phrase into the vector (last parameter).

For the functiondisplay_phrase(), the function replaced displays the contents of the vector passed in.

The code: the main method should not need to be changed

#include <cstdlib>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

// Function prototypes
void replace(string & phrase, const string & letter, const string & replacement, vector<char> & text);
void display_phrase(const vector<char> & text);

int main()
{
string phrase, letter, replacement;
vector<char> text_vec;

cout << "Enter phrase: ";
getline(cin, phrase);

if (phrase.length() > 0)
{
   cout << "Enter letter to replace: ";
   getline(cin, letter);

   if (letter.length() == 1)
   {
       cout << "Enter replacement letter: ";
       getline(cin, replacement);
  
       if (replacement.length() == 1)
       {
           replace(phrase, letter, replacement, text_vec);
           cout << "String phrase: " << phrase << endl;
           cout << "Vector phrase: ";
           display_phrase(text_vec);
           cout << endl;
       }
       else
       {
           cout << "Replacement letter must be a single letter" << endl;
       }
   }
   else
   {
       cout << "Letter to replace must be a single letter" << endl;
   }
}
  
return 0;
}

// FUNCTION
void replace(string & phrase, const string & letter, const string & replacement, vector<char> & text)
{
   // Insert your code here
}

void display_phrase(const vector<char> & text)
{
   // Insert your code here
}

Answer 1

Code:

#include <cstdlib>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

// Function prototypes
void replace(string & phrase, const string & letter, const string & replacement, vector<char> & text);
void display_phrase(const vector<char> & text);

int main()
{
string phrase, letter, replacement;
vector<char> text_vec;

cout << "Enter phrase: ";
getline(cin, phrase);

if (phrase.length() > 0)
{
cout << "Enter letter to replace: ";
getline(cin, letter);

if (letter.length() == 1)
{
cout << "Enter replacement letter: ";
getline(cin, replacement);
  
if (replacement.length() == 1)
{
replace(phrase, letter, replacement, text_vec);
cout << "String phrase: " << phrase << endl;
cout << "Vector phrase: ";
display_phrase(text_vec);
cout << endl;
}
else
{
cout << "Replacement letter must be a single letter" << endl;
}
}
else
{
cout << "Letter to replace must be a single letter" << endl;
}
}
  
return 0;
}

// FUNCTION
void replace(string & phrase, const string & letter, const string & replacement, vector<char> & text)
{
// Insert your code here
vector<char> v(phrase.length());
text=v;
for(int i=0;i<phrase.length();i++)
{
text.push_back(phrase.at(i));
}
//cout<<text;
for(std::vector<int>::size_type it = 0; it != text.size(); it++)
{
if(text[it]==letter.at(0)) //Comparing both the characters
{
text[it]=replacement.at(0);
}
}
}

void display_phrase(const vector<char> & text)
{
// Insert your code here
for(std::vector<int>::size_type it = 0; it != text.size(); it++) {
cout<<text[it]; //Printing modified String which is in form of vector
}
}

Sample i/o:

Explanation:

A vector named v of length of the string has been created. The created vector has been assigned to the text. Now  size_type type of iteration is used and when ever there is a match with given character the replacement character is given. A sample input output was given for better understanding