Vertical Histogram array printing issues

Question

I'm trying to make a vertical histogram. I'm a little confused because in the instructions it says "A standard terminal window is 80 character-columns across. If we limit the number of columns we can graph to a maximum of 80, we know how large an array we need to allocate and this program is simple to write."

What I understand from this is to create an array of length 80 and store input from scanf.

int arr[80];

for(i=0;i<80;i++)
{
scanf("%d", &arr[i]);
}

Then I find the maximum element in the array and use a while loop to print the histogram:

max = arr[0];

for(i=0;i<80;i++)
{
   if(arr[i]>max)
   {
     max = arr[i];
   }
}


while(max!=0)
{
   for(k=0;k<80;k++)
   {
     if(arr[k]<max)
     {
       printf(" ");
     }
     else
     {
        printf("#");
     }
   }
   printf("\n");

  max--;
}

However when I run the program, nothing prints so I don't think it even reaches that point...I have not learned about malloc yet so I know I don't have to use that. Here is an example of what it should look like:

Input:
 1 4 2 3

Output:
  #  
  #   #
  # # #
# # # #

Answer 1

You are probably running into problems with this:

scanf("%d", &arr[i]);

since there is no delimiter (such as a newline or space) which scanf can use to decide when a number is completed. People work around scanf limitations by adding a dummy parameter to absorb the whitespace, eg,

scanf("%d%s", &arr[i], dummy);

However that runs into problems with the length of the dummy parameter.