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Common string handling pitfalls in C programming

_Preface: This is a self-answered Q&A meant as a C string handling FAQ. It will ask several questions at once which isn't ideal, but they are all closely related and I'd rather not fragment the post into several._
~~---~~
When reading C programming forums or code written by beginners, there is a number of frequently recurring bugs related to string handling. These are not only written by complete beginners, but as often by experienced programmers coming from a higher level language and picking up C.
The common bugs originates from them assuming that C like most languages has a built-in string class which will handle all string handling and memory allocation for them. Here follows some frequently occurring bugs and their related questions:
~~---~~
- Bug 1) `char str = "hello";`.
~~This will luckily not even compile if the compiler is configured correctly, see [What compiler options are recommended for beginners learning C?](https://software.codidact.com/posts/282565)~~
~~**Question: Why doesn't this work? Does C have a string class?**~~
~~---~~
~~- Bug 2) `char str[5] = "hello";`.~~
Compiles just fine, yet when printing this there will be garbage printed or other strange behavior. This bug is related to character arrays and missing null termination.
~~**Question: What exactly does a string consist of in C?**~~
~~---~~
~~- Bug 3) `char* str; scanf("%s", str);`~~
Compiles just fine, though if lucky there can be warnings. This bug is related to memory allocation.
~~**Question: Who is responsible for allocating memory for the string?**~~
~~---~~
- Bug 4) `char* str = malloc(5+1); str = "hello";`
~~Compiles just fine, though there are memory leaks.~~
~~**Question: How can a string get assigned a new value?**~~
~~---~~
~~- Bug 5) `char str[5+1] = "hello";` ... `if(str == "hello")`.~~
~~Compiles just fine but gives the wrong results.~~
~~**Question: How do you properly compare strings?**~~

<section class="notice">
This is a self-answered Q&A meant as a C string handling FAQ. It will ask several questions at once which isn't ideal, but they are all closely related and I'd rather not fragment the post into several._
</section>
Code written by beginners to C, or found on C programming forums, frequently contains a few specific string handling bugs. Even experienced programmers coming from a higher level language and picking up C may make these mistakes.
These bugs seem to result from expecting C to have a built-in string class (like most languages do) which would handle all string operations and memory allocation for them.
Here are some frequently occurring bugs with corresponding questions:
1. `char str = "hello";`.
This will luckily not even compile if the compiler is configured correctly, see [What compiler options are recommended for beginners learning C?](https://software.codidact.com/posts/282565)
**Question: Why doesn't this work? Does C have a string class?**
1. `char str[5] = "hello";`.
Compiles just fine, yet when printing this there will be garbage printed or other strange behavior. This bug is related to character arrays and missing null termination.
**Question: What exactly does a string consist of in C?**
1. `char* str; scanf("%s", str);`
Compiles just fine, though if lucky there can be warnings. This bug is related to memory allocation.
**Question: Who is responsible for allocating memory for the string?**
1. `char* str = malloc(5+1); str = "hello";`
Compiles just fine, though there are memory leaks.
**Question: How can a string get assigned a new value?**
1. `char str[5+1] = "hello";` ... `if(str == "hello")`.
Compiles just fine but gives the wrong results.
**Question: How do you properly compare strings?**

c string string-literals string.h

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