how to use scanf in a custom function in C

Question

Before I start please keep in mind that I am still learning and need help with some stuff that may be easy to you but not to me. So here we go. I am having trouble using scanf in a custom function. It will not let me type anything. It just keeps running forever unless I stop it. How can I get scanf to work here:

#include <stdio.h>
#include <stdlib.h>

void function ();

int main (void)
{
  char sel;
  function ();
  return 0;
}

void function ()
{
  scanf("%c",&sel);
}

It's hard to help you without knowing what it is you're trying to do and what behavior you are seeing. — David Schwartz, May 27 '16 at 23:32
Could you give a more detailed description about how your program isn't working? What are you using to compile it? How are you compiling it with that? What happens when you run it? — amaurea, May 27 '16 at 23:33
Just trying to help out with general coding, try not to use global variables unless they're necessary, it would be enough if it's local to main. There's no point in creating a function with only calls scanf with a global variable. — Mr. Branch, May 27 '16 at 23:33
@jacobgarner Don't remove curly braces around loop body: http://stackoverflow.com/questions/359732/why-is-it-considered-a-bad-practice-to-omit-curly-braces?lq=1 — Barmar, May 27 '16 at 23:47
@MartinJames it will not let me type anything in. Nor will it print if you use printf. — Jacob Garner, May 28 '16 at 00:22
Well now you have `function()` trying to access a variable that's local to `main()`. — jamesdlin, May 28 '16 at 01:00
When you ask questions about code, you really should copy and paste the exact code. It's also weird that you completely changed the code after you asked the question, and the accepted answer makes *no* sense with the current version. — jamesdlin, Jun 05 '16 at 15:55

Priyansh Goel · Accepted Answer · 2016-05-27T23:34:24.610

0

There is no problem with scanf. The problem is with your loop. l = 1 and l++ will always keep l >= 0 and hence it will keep on taking input infinite times. Also, it will keep on overriding the value of var.a with every input

edited May 27 '16 at 23:34

answered May 27 '16 at 23:16

Priyansh Goel

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Ok. but..I need a loop (of any type) to keep going forward forever. Any suggestions? – Jacob Garner May 27 '16 at 23:23
Do you want to take the input infinitely? If yes, then the above code has no issues. What is the problem you are facing in scanf then? – Priyansh Goel May 27 '16 at 23:24
Yes, but it won't even let me type anything in. I even got rid of the loop and it did the same thing happened! – Jacob Garner May 27 '16 at 23:26
@JacobGarner: I compiled your program as it is, and it lets me type things in. How are you compiling, and how are you running it? – amaurea May 27 '16 at 23:28
Even me! There is no problem in your code if you want to take input for infinite number of times ( Though it doesn't make sense to me ) . You can do printf below your scanf to see your code working – Priyansh Goel May 27 '16 at 23:30
@amaurea I compile it in CCP (that is the C language type) – Jacob Garner May 27 '16 at 23:30
@PriyanshGoel that won't work either. – Jacob Garner May 27 '16 at 23:33
I suppose that you are making a .c file and compiling it using cc/gcc command – Priyansh Goel May 27 '16 at 23:35
@PriyanshGoel it says that my C-language is in CCP – Jacob Garner May 27 '16 at 23:47
@JacobGarner What's that supposed to mean, .cpp is traditionally the file extension for C++ files, not C if that's what you mean, but I have no idea what CCP is. – Lemon Drop May 27 '16 at 23:48
Do avoid integer overflow. `l >= 0` -> `l < INT_MAX` after including `limits.h`, or simply `for(;;)` because `l` is not used in the loop. – MikeCAT May 27 '16 at 23:52
@lemondrop my compiler does not have options for what you're talking about. So I assume it's the same. – Jacob Garner May 27 '16 at 23:52
1. It will not be "infinite" numbr of time. 2. The call to `scanf()` is wrong because there is no checking of the return value. – Iharob Al Asimi May 28 '16 at 00:05

how to use scanf in a custom function in C

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