Summary - Strings

Combine concatenation, substr and find to write a business card.

Summary - Strings

In this group you learned the core tools of std::string: concatenation with +, appending with append, counting characters with length/size, slicing with substr and searching with find.

Now you will combine them in a small business card app. First you will join the first and last name with a space, then take the initials from the resulting string with substr. Such combined tasks appear all the time in real projects.

Exercise Business card - full name

The firstName and lastName variables are given. Build fullName as firstName + " " + lastName and print it with std::cout.

Show example solution

#include <iostream>
#include <string>

int main() {
    std::string firstName = "Alex";
    std::string lastName = "Brown";
    std::string fullName = firstName + " " + lastName;
    std::cout << fullName << std::endl;
    return 0;
}

Exercise Business card - initials

The s variable is set to "Merhaba". Take the first three characters with s.substr(0, 3) into the part variable and print it with std::cout. The output must be Mer.

Show example solution

#include <iostream>
#include <string>

int main() {
    std::string s = "Merhaba";
    std::string part = s.substr(0, 3);
    std::cout << part << std::endl;
    return 0;
}

Next step

Well done! You learned the five most common tools of std::string: + for concatenation, append to add at the end, length for the count, substr for slicing and find for searching.

In the next group you will make your program behave differently in different situations with conditional expressions. Building logic with if, else and switch is the foundation of real applications.

Test yourself

What does std::string s = "Welcome"; s.find("co") return?
```
std::string s = "Welcome";
s.find("co")
```
- 5
- -1
- 0
- 3
Show answer

3 — "co" starts at index 3; find returns 3.

Write the substr call

std::string s = "Welcome";
std::string first3 = s____(0, 3);

Show answer

std::string s = "Welcome";
std::string first3 = s.substr(0, 3);

Next lesson: The if statement

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