scanf function not working on GCC ubuntu [closed] - c

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I'm starting to write a C code after a gap of almost 10 year. I was teaching my sister and unfortunately got stuck at a very basic scanf() function for a simple interest program on Ubuntu.
My program is not giving any compilation error but it's not showing anything on screen
Here is the code:
#include <stdio.h>
int main()
{
int p,n;
float r,si;
printf("enter values of p,n,r");
scanf("%d %d %f",&p,&n,&r);
si = p*n*r/100;
printf("%f" , si);
return 0;
}

Answer 1

This is a common "issue" when trying to printf() and scanf() after one another. The operating system buffers stdin and stdout in order to increase performance and only flushes them when necessary. You can explicitly flush stdout by calling fflush(stdout); right after printf().
See C/C++ printf() before scanf() issue.
Your code would end up looking like
#include <stdio.h>
int main()
{
int p,n;
float r,si;
printf("enter values of p,n,r\n");
fflush(stdout); // Force stdout to be flushed
scanf("%d %d %f",&p,&n,&r);
si = p*n*r/100;
printf("%f" , si);
return 0;
}

Answer 2

I think you are just not looking at your console properly. The output "si" is getting printed on the same line as your first printf since you do not have a newline inserted at the end of it.

Answer 3

When you say
not showing anything on screen
(emphasis added), I take you to mean that when you run it, it's not displaying the data-entry prompt you're printing. This would be because the standard output is line-buffered by default when connected to a terminal -- it will buffer the output in memory before printing it, until either the buffer is filled, or (because line buffered) a newline is output, or the stream is closed (including when the program terminates normally).
One way to cause the prompt to be displayed, therefore, is to append a newline to it:
printf("enter values of p,n,r\n");
Another is to use an output function that automatically appends a newline:
puts("enter values of p,n,r");
If you want to ensure that the output appears even though no newline has been sent then you can flush the stream (standard output in this case) instead:
printf("enter values of p,n,r: ");
fflush(stdout);

Answer 4

Your code worked perfectly for me in my Ubuntu system.This may be because of the mistake of the IDE you are using.
Try running code in Ubuntu this way:-
save file as program.c on desktop.
open terminal and type cd Desktop (navigate to desktop).
compile code by typing gcc -o program program.c .
run program by typing ./program.