String functions overview in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the std::string::length() function do?

It returns the number of characters in the string, excluding the null terminator.

beginner

How do you convert a std::string to a C-style string?

Use the c_str() function, which returns a pointer to a null-terminated character array.

intermediate

What is the purpose of std::string::substr()?

It extracts a substring from the string, starting at a given position and optionally for a given length.

intermediate

How does std::string::find() work?

It searches for a substring or character inside the string and returns the position of the first occurrence or std::string::npos if not found.

beginner

What does std::string::append() do?

It adds characters or another string to the end of the current string, increasing its length.

Which function returns the length of a std::string?

A strlen()

B size()

C count()

D length()

length() and size() both return the string length in C++, but length() is the most common for strings. strlen() is for C-style strings.

What does std::string::find() return if the substring is not found?

A <code>std::string::npos</code>

B -1

C 0

D Throws an exception

If the substring is not found, find() returns std::string::npos, a special constant indicating no match.

Which function would you use to get a part of a string starting at position 3 with length 5?

A slice(3, 5)

B substring(3, 5)

C substr(3, 5)

D cut(3, 5)

substr() extracts a substring from a string starting at the given position and length.

How do you add "world" to the end of a string s?

A s.push_back("world")

B s.add("world")

C s.insert("world")

D s.append("world")

append() adds characters or strings to the end of a std::string.

Which function returns a pointer to a C-style string from a std::string?

A c_str()

B data()

C to_cstring()

D ptr()

c_str() returns a pointer to a null-terminated C-style string.

Explain how to find a substring inside a std::string and handle the case when it is not found.

Think about the function that searches and what it returns if no match.

Describe how to extract a part of a string and how to add text to the end of a string in C++.

Two common string operations: cutting and joining.