simple c program not printing output

Question

I have a simple c program

#include <stdio.h>

int add(int, int);
int add (int a, int b) {
   return a+b;
}

int main(void) {
  int a, b, c;

  printf("Enter the 1st number ");
  scanf("%d",&a);
  printf("Enter the 2nd number ");
  scanf("%d",&b);
  c = add(a, b);
  printf("The value is %d ", c);
  return (0);
}

I am compiling the program with cc main.c and when I am running the program with ./a.out
I am not getting any output in the console.

@VladfromMoscow: It's the English word "I", the start of a new phrase. "I am not getting any output". I realise that it's difficult to recognise it in its correct uppercase form, on a website where people largely write it like "i" instead for no discernible reason. — Lightness Races in Orbit, Aug 09 '15 at 13:46
Maybe this is duplication but here is an example code which makes reading easier — Adam, Nov 05 '17 at 08:48

score 5 · Accepted Answer · edited May 23 '17 at 12:00

5

The output is buffered for performance reasons. Replace

printf("The value is %d ", c);

with

printf("The value is %d\n", c);

or use fflush(stdout);.

See Why does printf not flush after the call unless a newline is in the format string?

edited May 23 '17 at 12:00

Community

1
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answered Aug 09 '15 at 13:43

user2644013

172
1
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It would still flush on program end. – Lightness Races in Orbit Aug 09 '15 at 13:48
1

I'm not sure why, but sometimes the newline character is not enough. I'm running mingw gcc (can't remember the exact version, but it might 4.9.2) and even with a newline character at the end of a string doesn't output it unless fflush(stdout) is called. P.S. who downvoted? It's a good answer, no? – kbau Aug 09 '15 at 13:48

simple c program not printing output

1 Answers1