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C Module 4 Quiz, Question #4

I am so confused about question number 4. I initially felt like I understood pointers and the * and & operators, but I cannot seem to find anything on how to call this particular function pointer. Honestly, the whole idea of a function pointer seems completely convoluted to me; I just don't get it. If anybody has some insight as to the significance, syntax, or just the answer itself that would be really helpful. Thanks!

13th May 2021, 12:49 AM
C-Boogie
C-Boogie - avatar
9 ответов
+ 4
Perfect Answer : #First blank is Void #Second blank is & #Third blank is *
28th Sep 2022, 1:18 AM
Kayala Venkata Ramana
Kayala Venkata Ramana - avatar
+ 2
Fill in the blanks to triple the value of the num variable via the void pointer. The correct ans : float num = 3.14; void *ptr = & num; * ((float*)ptr) *= 3;
7th Jul 2021, 1:03 PM
NagaSundar M
NagaSundar M - avatar
0
Not a function pointer :) As Thirt13n pointed out we are just converting a float to a void* and back. Truthfully C doesn't do a very good job of selling function pointers, the syntax is absolutely terrible. Significance? In C probably not so much, but I see you did javascript aswell. This stuff is really common in js: var f = function () { console.log("Hi!"); }; button.addEventListener("click", f); In other words we can put functions in variables. Super useful, js devs do it *everywhere*. Now in js everything is a `var` and it just sort of works somehow, but in C all variables need to have a type; and if you have a function in a variable, the variable's type needs to reflect the function's type somehow. Thus we end up with gnarly stuff like `void (*foo)(int, int)`. Other languages have prettier syntax for function types but C is old what are you gonna do. To translate the js example into nonsense C: void f() { printf("Hi!"); } void onEvent (char* what, void (*fp)()){ ... } onEvent("click", &f);
13th May 2021, 1:44 AM
Schindlabua
Schindlabua - avatar
0
float num=3.14; void *ptr=# *((float*)ptr)*=3;
13th Oct 2022, 3:47 AM
Rahul Gorai
Rahul Gorai - avatar
0
ans =1
18th Nov 2022, 9:07 AM
Kelvin Limo
0
create a pointer to the variable called demo then output its value using the pointer
6th Nov 2023, 8:18 PM
Deepak Kumar
Deepak Kumar - avatar
0
What is The largest of the arrays.if arrays form 35 12 3 8
30th Dec 2023, 8:45 PM
Rabira Imana
Rabira Imana - avatar
0
Fill in the blanks to declare a string, then output its 5th character. x[] = "Hello there ; printf(" ", x[ ]);
30th May 2024, 2:03 PM
Jagadeeswari Guda
Jagadeeswari Guda - avatar
- 3
Q.triple the value of " num " using void pointer float num=3.14; .......ptr=....num; ....((float*)ptr)*=3; >>>as in question pointer " ptr " is void first blank's answer is " void " and then addressof " & " >>>here num is casted to float , because when we dereference void pointer we must first type cast the pointer before dereferencing with " * " . ptr points to address of " num " if we dereference " ptr " then only we can make multiply to num , so third blank is for dereference " * " ; here third " * " for multiplication ! HOPE THIS HELP ! (please correct me if I'm wrong)
13th May 2021, 1:14 AM
Giriraj Yalpalwar
Giriraj Yalpalwar - avatar