C program shows no error but doesn't show output - c

Question

Roy wants to change his profile picture on Facebook. Now Facebook has some restriction over the dimension of picture that we can upload.
Minimum dimension of the picture can be L x L, where L is the length of the side of square.
Now Roy has N photos of various dimensions.
Dimension of a photo is denoted as W x H
where W - width of the photo and H - Height of the photo
When any photo is uploaded following events may occur:
If any of the width or height is less than L, user is prompted to upload another one. Print "UPLOAD ANOTHER" in this case.
If width and height are both large enough and
(a) if the photo is already square then it is accepted. Print "ACCEPTED" in this case.
(b) else user is prompted to crop it. Print "CROP IT" in this case.
Code:
#include <stdio.h>
#include <stdlib.h>
int main (void)
{
int len; /* len is the length of the side of square */
scanf("%d",&len);
int test;
scanf("%d",&test);
while(test--)
{
int w,h;
/* w - width of the photo and h- Height of the photo */
scanf("%d %d",&w,&h);
if(w==len && h==len)
{
printf("ACCEPTED\n");
}
else if(w>len || w==len && h>len || h==len)
{
printf("CROP IT\n");
}
else
{
printf("UPLOAD ANOTHER\n");/* print */
}
}
return 0;/* success */
}

Answer 1

If your problem is that you're seeing no output at all, it's likely because it's running in an IDE and the output window is closing before you can see it. Judicious use of a getchar() at the end of main() may be all you need to fix this, though I'd probably prefer to just run it from the command line.
In any case, since && has a higher precedence than ||, your second condition is effectively:
else if ((w > len) || (w == len && h > len) || (h == len))
which is clearly wrong since having a photo with width more than what was necessary would result in a request for cropping regardless of the other sub-conditions.
You would be better off following the textual specs more closely so that you can actually check it more easily. That would entail something like (with slightly simplified specs still meeting the original intent):
If any of the width or height is less than L, user is prompted to upload another one.
Otherwise both are large enough. If the photo is already square then it is accepted.
Otherwise user is prompted to crop it.
The code for that is a much simpler:
if ((w < len) || (h < len)) {
puts ("UPLOAD ANOTHER");
} else if (h == w) { // Both large enough otherwise previous
puts ("ACCEPTED"); // condition would have been true.
} else {
puts ("CROP IT");
}

Answer 2

Due to operator precedence,
else if(w>len || w==len && h>len || h==len)
is equivalent to:
else if(w>len || (w==len && h>len) || h==len)
What you need to use is:
else if( (w>len || w==len) && (h>len || h==len) && (w == h) )
You can simplify that to:
else if( w >= len && h >= len && w == h )
which can be further simplified to:
else if( w >= len && w == h )

Answer 3

It will show output but the program runs faster than you expect. It will close as soon as the output is displayed . It will not wait till you read it.
So use getch(); declared in conio.h to get a single key press as input after you have printed all the output (right before the return statement. It will make the program wait for the user to press a key before exiting.

Answer 4

here is the screenshot. it is running without error on me.
NOTE: This is not an answer. But this is just the only way to give picture example :) no need to up
Maybe you only need to put getchar(); at the end of the code before return to let the screen to pause for a while. it is just exiting very fast