Lesson # 6. Using strings

To do: Create a function to check if input text contains a combination of letters 'mo'. Return 1 (if found) or 0 (if not found). It is not allowed to use any standard functions. To store the text, you should use a string type variable.

Note 1: The signature of the function must be as following:

bool findMo(string s)

Note 2: To check two or more conditions in if statement you must use && (logical and):

if (condition_1 && condition_2){
}

Expected output:

task 1
result for 'Hello world' is:
0
---
task 1
result for 'My mom' is:
result:
1

To do: Create a function to check if the value of string variable contains the word 'dog'. Return 1 (if found) or 0 (if not found). You should use c character string and a pointer. It is not allowed to use any standard functions.

Note 1: The signature of the function must be as following:

bool findMo(char* p)

Expected output:

task 2
the string is: Hello world
result:
0
---
task 2
Enter a sentence:
the string is: my dog is nice
result:
1

To do: A sentence is given: str = "word1 word2 word3 word4". Calculate the number of words in it. It is not allowed to use any string standard functions.

Note 1: You have to count the number of words by the number of spaces between the words.

Note 2: Don't forget to check if the sentence contain extra spaces at the beginning and end of the sentence.

Note 3: The signature of the created function must be as following:

void countWords(string s, int& counter)

Expected output:

task 3
Enter a sentence:
>>>  word1 word2 word3 word4
result:
4

To do: A string is given. Check if its first and last characters match. Create a function named LastAndFirst to do the task. It is not allowed to use any string standard functions (except size() function).

Note 1: The signature of the created function must be as following:

bool LastAndFirst(string s)

Note 2: The size() method of the string can be useful to find the last character (s.size()).

Expected output:

task 4
for sentence Hello world
the result is:
false
---
task 4
for sentence lucky ball
result is:
true

To do: Create a function to check if the text contains the word cat. Print the position (order number) of the word in the text. You should use standard find function.

Note 1: The signature of the created function must be as follows:

void findCatFunction(string s, string s0)

Note 2: About find() function:

s.find(s0) // returns -1 if there are no matches of s0 in the text s

Expected output:

task 5
for text: cat word1 word3 word4
result :
cat is found at: 0
---
task 5
for text: word1 word3 word4
result :
cat is not found
---
task 5
for sentence: word1 cat word3 word4
result :
cat is found at: 6

To do: The strings S and S0 are given. Create a function to remove the last substring that matches S0 from the S string. If there are no matching substrings, then return the unchanged S string.

Note 1: You can use the rfind member function of the string class to find the last occurrence of a substring, and you can use the erase member function to delete.

Note 2: Look at the example to understand the way to use them.

Note 3: The signature of the function must be as follows:

string eraseLast(string s, string s0)
{
	// to do:
        // 
        //
	return s;
}

Expected output:

task 6:
string 1: it's possible to understand it
string 2: it
result: it's possible to understand

To do: A string containing at least one space character is given. Return the substring between the first and last spaces of the string. If the string contains single space, an empty string must be returned.

Note 1: You can use the substr member function of the string class to extract a substring.

Note 2: Look at the example to understand the way to use them.

Note 3: The signature of the function and the fragment of its code:

string betweenSpaces(string s)
{
	size_t f1, f2;
	f1 = s.find(" "); // the position of the first space
	f2 = s.rfind(" "); // the position of the last space
	// ...;
        // ...;
	return  // ...;
}

Expected output:

task 7:
string: it's possible to understand it
result : possible to understand