C++ Exercise Problem: Find word in text that the user has entered

Code:

---

#include <iostream>
#include <string>


using namespace std;


int main() {
       
        string text, ord;
        cout << "Type a sentence: ";
        getline(cin, text);
       
        cout << "Type a word: ";
        getline(cin, ord);
       
        // Find the first letter in the word
        int pos = text.find(ord.at(0), 0);
       
        // Find the last letter in the word
        int ord_langd = ord.length();
       
        string ordet;
       
        // Get word
        ordet = text.substr(pos, ord_langd);
       
        // Compare the text sentence to see
        // if the word the user entered exists in it
        // This is the problem that I struggle with.
        if () { // I can't complete the if statement
                cout << "Word does not exist" << endl;


        }
        else {
                cout << "Index: " << ord.at(0) << " " << pos << endl;
                cout << "Word: " << ordet << endl;
        }
       
        return 0;
}

---

I want the user to be able to input a full sentence like "How are you" and then the user is asked to enter a word "are". If the word "are" is in the sentence then the program should tell the user. If the word "are" isn't in the sentence then the program should tell the user that the word doesn't exist within the string.

Example:

Type a sentence: How are you
Type a word: are
The word "are" exists in your sentence

Example:
Type a sentence: How are you
Type a word: bye
The word "bye" doesn't exist in your sentence

I hope I'm clear enough so that you get what I mean. Otherwise ask me to clarify.

What are the possible return values for text.substr(pos, ord_langd)?

Unless your exercise demands it, I think it would be easiest if you searched the text string for the ord string directly. It doesn't check for word boundaries though. Maybe you could just surround ord with spaces prior to checking.

Code:

---

auto result = text.find(ord);

---

std::string::find returns the position if there is a match and std::string::npos otherwise. So you could for instance create an if condition to compare result with that "no match" value. I'll leave that to you :)

Well, According to my exercise and according to Chapter 4 - Strings in my text book. We've only seen the string functions:

find(word, start)
substr(start, end)
at(index)
length(), size()

So I don't think I'm allowed to use:

Code:

---

auto int result = text.find(ord);

---

Since the text book have only covered these string functions and
actually nothing about the keyword auto.

Quote:

---

Originally Posted by DecoratorFawn82

We've only seen the string functions:

find(word, start)
substr(start, end)
at(index)
length(), size()

---

find(word) is equivalent to find(word, 0).

And uh, I zeroed in on the wrong part of your code in my previous post as I did not expect that you would have a different approach. My point is that "std::string::find returns the position if there is a match and std::string::npos otherwise."

Quote:

---

Originally Posted by DecoratorFawn82

(...)
Since the text book have only covered these string functions and
actually nothing about the keyword auto.

---

Yah ok, that's fair enough. So from what I understand, you:
1. Try to find the first letter of ord in text and store that location in pos.
2. Get a substring (ordet) from text with the length of ort, starting at pos.
3. Compare ordet to ort to see if they are actually the same word and don't just share the same first and last letter.

If that's what you want to do, then you can just use the == operator to compare those two strings, the same way you would e.g. compare two integers.

Note that you should generally use 64-bit unsigned integers to handle container positions. Using int could lead to unexpected behaviour later on.

Code:

---

size_t pos = text.find(ord.at(0)); // size_t can hold any value find() returns, int cannot
size_t ord_langd = ord.length();

---

As a matter of style, I would advise to initialize your variables directly if possible.

Code:

---

int ord_langd = ord.length();
string ordet = text.substr(pos, ord_langd); // we assign to ordet on declaration

---

You may also notice that ord_langd gets used immediately, so you could get rid of it unless it hurts clarity.

Code:

---

string ordet = text.substr(pos, ord.length());

---