String helpers
- C++ course
- Intermediate
- Lesson 20/116
- 6 min
Add and test string processing functions.
String helpers
In this lesson we add the first helper method to the Helpers class: capitalize. This method uppercases the first letter of a string. In C++ the std::toupper function uppercases a single character.
Example: static std::string capitalize(std::string text) { if (text.empty()) return text; text[0] = std::toupper(text[0]); return text; }. Here text.empty() checks for an empty string; text[0] accesses the first character. Call: Helpers::capitalize("hello") returns "Hello". We take the previous lesson's skeleton and add this method.
Calling the method
A static method is called with the class name and two colons (::). No instance is needed: Helpers::capitalize("hello"). You can print the returned value with std::cout.
To see output on separate lines, use std::endl: std::cout << Helpers::capitalize("hello") << std::endl;. This prints Hello and moves to the next line. After the previous lesson's "Ready" output, Hello appears on a new line. This way the output of two lessons accumulates.
Practice Add the capitalize method and call it
Take the previous lesson's Helpers skeleton. Under public: add static std::string capitalize(std::string text) with body if (text.empty()) return text; text[0] = std::toupper(text[0]); return text;. In main after std::cout << "Ready" << std::endl; add std::cout << Helpers::capitalize("hello");.
Starter code
#include <iostream>
#include <string>
class Helpers {
};
int main() {
std::cout << "Ready";
// Add the capitalize method and call it
return 0;
}Sample solution
#include <iostream>
#include <string>
#include <cctype>
class Helpers {
public:
static std::string capitalize(std::string text) {
if (text.empty()) return text;
text[0] = std::toupper(text[0]);
return text;
}
};
int main() {
std::cout << "Ready" << std::endl;
std::cout << Helpers::capitalize("hello");
return 0;
}Expected output
Ready Hello
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What does capitalize("hello") return?
Helpers::capitalize("hello")- "HELLO"
- "Hello" Correct answer
- "hello"
- "hELLO"
Explanation: Only the first letter is uppercased: Hello.
2 Uppercase the first letter
text[0] = std::____(text[0]);text[0] = std::toupper(text[0]);Explanation: std::toupper uppercases a single character.
3 Match each piece to its role
| Term | Meaning |
|---|---|
static |
Enables call without instance |
std::toupper |
Uppercases a character |
text.empty() |
Empty string check |
Helpers::capitalize |
Method call |