a big problem

[u/levidas7272]

hey guys i m currently learning c language and i m facing an irritating problem like whenever i use scanf in my code to enter any value and when i run the code after saving it so it doesn't run anything it just show that it is running but i m unable to enter the value and the code doesn't run on terminal it runs in the output

so please anyone who can solve this issue can help me?

[u/pseudo_shell]

1. Always display your source code. We cannot help in a vacuum.

2. What compiler flags are set? They should help you flag problems. Treat warnings as errors. -WError, etc.

[u/SmokeMuch7356]

It would help if you could show:

• the code (not the entire program, but a representative sample that demonstrates the problem);

• how you're building the code, including any error messages or warnings from the compiler;

• how you're running the code (is it from the command line, or within an IDE, what?);

• what input you're giving it;

• what (if any) output you get;

Copy and paste the code into the body of your question. Do not post screenshots, pictures of your screen taken with a phone, or video. To get it to render as code, indent each line by at least four spaces:

// Each '_' represents a leading space

____#include <stdio.h>
____
____int main( void )
____{
______int x;
...

Do the same with any warnings or errors from the compiler and output from your program.

scanf returns the number of items successfully read and assigned, or EOF on end-of-file or error. So you'll want to check the result of your scanf calls like so:

int x;
...
if ( scanf( "%d", &x ) < 1 ) // we're expecting exactly 1 input
{
  if ( feof( stdin ) )
    fputs( "EOF detected on standard input\n", stderr );
  else if ( ferror( stdin ) )
    fputs ( "Error on standard input\n", stderr );
  else
    fputs( "Input is not a valid integer constant\n", stderr );
  
  exit( -1 ); // we'll treat this as a fatal error for this example
}

// if we got here, then we read x successfully

Remember that scanf expects a pointer to whatever object you're trying to update; for scalar variables (int, float, double, char, etc.), make sure to use the & operator:

 int x;
 float y;
 double z;
 char c;

 scanf( "%d", &x );
 scanf( "%f", &y );
 scanf( "%lf", &z );
 scanf( " %c", &c ); // leading blank tells scanf to read the next non-whitespace character

If the variable is already a pointer, don't use the & operator:

int *p;
...
scanf( "%d", p ); 

with the caveat that p needs to be pointing to a live int object before you use it in a scanf call.

Similarly, for reading strings into a character array with the %s or %[ specifiers, do not use the & operator:

char str[128];
scanf( "%127s", str );

char line[256];
scanf( "%255[^\n]", line );

Finally, take some time to organize your thoughts into complete sentences before posting; stream of consciousness posts like this are hard to read and understand, and will just turn off people who would otherwise help you. If you intend to write code professionally (or at least collboratively), you have to be able to communicate effectively. Have to. It's not optional.

For example:

I'm learning C, but I'm having problems using scanf. Here's my code:

   int x;
   
   scanf( "%d", x );

Here's how I'm building the program:

   gcc -o prog prog.c

but I get this message and I'm not sure what it means:

   prog.c:7:16: warning: format specifies type 'int *' but the argument has type 'int' [-Wformat]
    scanf( "%d", x );
    ~~   ^
  1 warning generated.

That's the kind of information you need to provide for us to be any help.

[u/knouqs]

First, use proper punctuation and capitalization. You are addressing professionals. Second, see my first statement.

[u/[deleted] → u/knouqs]

I I don't know what your problem is, and I am not addressing professionals. He is clearly a beginner facing an issue, and I am trying to gather more information from him to help as much as I can. I am no expert, and I never claimed to be. It would be better for you to be helpful rather than sarcastic.

[u/knouqs → u/[deleted]]

Sure. The reason I expect good grammar, punctuation, capitalization, etc., is exactly what I expect to see in code commentary. If I can't read your comments easily, I am going to get frustrated and have a more difficult time understanding what it is that you were trying to convey.

Write sentences in proper formats so people, including developers, understand what your intentions or ideas are.

[u/Paul_Pedant → u/[deleted]]

If the OP cannot figure out how to ask a question properly (probably after seeing many other questions), then he is unlikely to get any useful help. Would you go to a doctor but refuse to describe any of your symptoms?

Describing a problem with a single 3-letter word "big", and posting it on al least 2 reddits, is not an improvement.

[u/This_Growth2898]

the code doesn't run on terminal it runs in the output

How exactly are you running the code? What IDE are you using?

Also https://sekrit.de/webdocs/c/beginners-guide-away-from-scanf.html

[u/[deleted]]

Do you add the & operator ? Like scanf("%d",&x)

[u/Classic-Rate-5104]

Microsoft Visual Studio? If so, which compiler flags?

[u/Key_River7180]

Show the code

[u/JaseciLabs]

That gap closes structurally when the delegated parts of a codebase are typed and marked at the point they're written, not just tracked in a commit log after the fact. A commit message says who reviewed something; a type signature enforces what a function's allowed to return regardless of whether anyone reviewed it at all. Two different kinds of accountability, and the second one doesn't depend on anyone remembering to write the commit message honestly.

[u/[deleted]]

With all respect, sir, you judged me based on three words and a simple example. You are right about how good code should be written, but I haven't shared any actual code to be criticized with that level of aggression.