Whale Talk vector<char> and vector<std::string> not interchangeable? C++

Computer Science
1

learn-cpp/5-vectors/whale.cpp at master · Codecademy/learn-cpp · GitHub

I’ve been trying to do whale talk in C++ for the longest time and then I found something. Maybe I’m not understanding this correctly…

#include <iostream>
#include <vector>
#include <string>

int main() {
  std::string input = "a whale of a deal!";
  std::vector<char> vowels = {'a','e','i','o','u'};
  std::vector<char> result;
  // more code...

I got the main part of the code correct. However, how come we can’t use vectorstd::string? I had it like that originally since that’s how the previous section had us do, but this time I got massive errors. The moment I changed it to vector everything worked perfectly. How?

And on the flip side, how come we can’t substitute char for std::string for the input string?

Can someone help me understand this? I’m very confused and would really like to figure this out before moving on! Any help is greatly appreciated!

2

Yes, a char and a string are inherently different data types in C++, there’s a lot of detail to how they are and why it doesn’t make sense for them to be interchangeable. However, you can always cast a char as a string so you should consider that as well.

Some differences:

  • size in memory
  • stack vs heap allocation
  • chars are basically ascii
  • strings can deal with utf-8
  • string have a lot of similarity to dynamic arrays (std::vectors) in terms of memory allocation

Casting can be as simple as

char c = 'a';
std::string s = std::string(1, c);

technically not a cast but virtually can be used the same way when necessary.