Comments by "⃠" (@U20E0) on "Fireship"
channel.
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( warning: length )
I found 2 interesting ones:
You can attempt to modify a string literal in C:
“abcdefg”[1] = ‘x’;
you can deference a void pointer in C, and cast the result of that to void.
And an obvious one:
C allows implicit casting of void* to any integer type, C++ requires an explicit cast
And a few practical ones:
In C++, only one “member” of a union can be “active” at a time, which imp defeats the purpose of a union.
this:
union u
{
float f,
int i
};
u.i = 3;
return u.f;
is valid C but undefined behavior in C++
C allows designed initialization in any order, does not require you to initialize any member, and allows initialization of subobjects and array members.
You can redeclare a global variable in C
global variables always have external linkage in C unless else specified. In C++ constant globals are internal unless else specified.
C allows you to buffer overflow yourself in dumb ways:
char c[2] = “abcdefgh”;
The size of a character literal is that of an int in C, but that of a char in C++
And a few less practical ones:
You can call main() in C
You can define main() with any return type in C.
in C, for a function declared as
int function() {}
calling it with arguments will not result in an error, unlike with
int function(void) {}
you can declare a constant without defining it in C
And a few obscure ones:
C allows a type definition anywhere where it allows a type:
void f ( struct s { int x } s );
C++ would give an error.
you can use prefix ++ and — on a bool in C
you can goto over a declaration in C
given struct S { int i : 1; } S;
sizeof( 1, s.i ); is valid C but invalid C++
Someone else can explain why
you can declare something as auto without defining it in C
you can put way too many const modifiers on a type in C.
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