Thread: Need help with C homework problem

Hello,


My name is ali and I am currently enrolled in edx.org program for computer science. On my problem set I was assign to create the pillars in mario:


jharvard@appliance (~/Dropbox/pset1): ./mario
Height: 8
##
###
####
#####
######
#######
########
#########

****The pillars are aligned to the left and not right but for some reason it won't let me post it that way.****


I have to first prompt the user for the half-pyramid's height, a non-negative integer no greater than 23. (The height of the half-pyramid pictured above happens to be 8.) If the user fails to provide a non-negative integer no greater than 23, you should re-prompt for the same again. Then, generate (with the help of printf and one or more loops) the desired half-pyramid. Also I have take care to align the bottom-left corner of your half-pyramid with the left-hand edge of your terminal window.


So far this is what I got from my solution. But the problem is They don't align properly and I don't understand how to use the \n in a loop to make that happen:

Code:

#include <stdio.h>
 
int main(void)
{
    int h, s, i;
        
        do
        {
            printf("Height: ");
            scanf("%d", &h);
        }
        while(h <= 0 || h > 23);
        
        for(s = 0; s < h - 1; s++)
        {
            printf(" ");
        }    
        for(i = 0;i < h ; i++)
        {   
            printf("#");
        }    
        
        
        return 0;
    
}

I can only use "do" "while" and "for" to solve this problem. I would really appreciate it if someone could guide me here

> int h, s, i;
Consider naming your variables things like
int numSpaces, numHashes, lineNumber;

Then your code might look like this.

Code:

for ( lineNumber = 1 ; lineNumber <= 10 ; lineNumber++ ) {
    numSpaces = ?
    numHashes = ?
}

Once you've got the calculation for spaces and hashes sorted out, then you can do a simple loop to output the correct number of each symbol on a line.

As Adak said, two nested loop does the job.

The following works for me

Code:

#include <stdio.h>

int main()
{
    int height = 0;
    int line = 0;
    int counter = 0;
    
    while (height <= 0 || height > 23)
    {
        printf("Enter the height: ");
        scanf("%d", &height);
    }
    printf("\n");
    
    for(line = 1; line <= height; line++)
    {
        for(counter = 1; counter <= line + 1; counter++)
            printf("#");
        
            printf("\n");
    }
    
    
    return 0;
}

And here is the result

Code:

$ gcc -Wall testscript.c -o testscript
$ ./testscript 
Enter the height: 100
Enter the height: 99
Enter the height: -54
Enter the height: 10

##
###
####
#####
######
#######
########
#########
##########
###########
$

Regards,
Dariyoosh

Salem, Adak, justine and dariyoosh thank you all for your replies. Dorivoosh I used your code as the frame but I still having some difficulties getting the right result. I need to have 7 space and start with 2 hashes. So if the user enters 0 or 1 then no pillars show but when they press 2 you will see the 2 pillars. After I have 9 stacks I don't want to print anymore and the last bottom pillar has to be with no spaces just 9 hashes. If the user enters "height: 10":

Height: 2
*******## (* represent space)

if they enter 3 they get:
[CODE]Height: 3
*******##
******###

I have got the the pillars to move to the right just like above but I am unable to stack them. How would I us the \n in a loop to get the pillars to stack. Also if a if the user enter a char how to i tell them to "retry: ".

My code so far:

Code:

#include <stdio.h>
int main()
{
    int height = 0;
    int space = 0;
    int hash = 0;
      
    while (height <= 0 || height > 23)
    {
        printf("Enter the height: ");
        scanf("%d", &height);
    } 


    for(space = 8; space >= height; space--)
        printf(" ");
         {
            for(hash = 0; hash <= space; hash++)
                printf("#");
                
                               
         }
    return 0;

This is what happens so far:

Code:

Enter the height: 1
         #jharvard@appliance (~/Dropbox/pset1): ./test2 
Enter the height: 2
        ##jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 3    
       ###jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 4
      ####jharvard@appliance (~/Dropbox/pset1): ./test2 
Enter the height: 5
     #####jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 6
    ######jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 7
   #######jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 8
  ########jharvard@appliance (~/Dropbox/pset1): ./test2
Enter the height: 9
 #########jharvard@appliance (~/Dropbox/pset1):

The pillars stack themselves. Just count the columns and the row, and get your arithmetic going.

Code:

spaces = widthOfRow - rowNum
if(row<2)     //correction for Mario's pillars
   spaces+=rowNum;

Although simple arithmetic will solve most of the problems, some fiddling and trial and error may be needed for some rows or columns. Just let the rows and column for loops, go around and around, and do as little logic as you can to make it right.

Normal thing is to overthink it, and try to put all the rows logic, into the column's for loop, as if the loop was only going to loop a few times, instead of several times.

Don't you print a newline at the end of each row? You should.

Originally Posted by dariyoosh

This is in contradiction with the OP, because first you said:


So finally the max is 8 or 23 ?

Also according to your code

Code:

while(h <= 0 || h > 23);

One reading this, understands that the user can enter 0 or 1 as a legal value for the height, but now you say for 0 and 1 nothing is printed.

The problem is not clear!

Regards,
Dariyoosh

dairyoosh i am sorry that what my mistake on the first post. The pillar has to be in this order:

Height = 8
  First row: 2 hashes, 7 spaces
  Second row: 3 #, 6 spaces
  Third row: 4 #, 5 spaces

my intructions were from the problem set were:

Write, in a file called mario.c in your ~/Dropbox/pset1 directory, a program that recreates this half-pyramid using hashes (#) for blocks. However, to make things more interesting, first prompt the user for the half-pyramid's height, a non-negative integer no greater than 23. (The height of the half-pyramid pictured above happens to be 8.) If the user fails to provide a non-negative integer no greater than 23, you should re-prompt for the same again. Then, generate (with the help of printfand one or more loops) the desired half-pyramid. Take care to align the bottom-left corner of your half-pyramid with the left-hand edge of your terminal window, as in the sample output below, wherein boldfaced text represents some user's input.

Code:

jharvard@appliance (~/Dropbox/pset1): ./mario
Height: 8 
*******## 
******### 
*****#### 
****##### 
***###### 
**####### 
*########
#########
```

Note that the rightmost two columns of blocks must be of the same height. No need to generate the pipe, clouds, numbers, text, or Mario himself. Just the half-pyramid! And be sure that main returns 0.
By contrast, if the user fails to provide a non-negative integer no greater than 23, your program's output should instead resemble the below, wherein boldfaced text again represents some user's input. (Recall that GetInt will handle some, but not all, re-prompting for you.)

Code:

jharvard@appliance (~/Dropbox/pset1): ./mario
Height: -2
Height: -1
Height: foo
Retry: bar
Retry: 1
##

Originally Posted by asexynerd

Adak can you give me a example of what you are saying because I am completely lost.

OK.

This is the figure with height = 8:

Code:

Height: 8
       ##  row 1 has 2 #'s
      ###  2
     ####  3
    #####  4
   ######  5
  #######  6
 ########  7
#########  8  has 9 #'s

Is that the right shape? I'm not that familiar with Mario!

So every row has 9 char's in it.

Code:

#include <stdio.h>

int main(void) {
   int r, c, spaces;
   int row,height;
   int col;

   printf("Enter height of the figure [1-23]: ");
   //scanf("%d",&height);
   printf("\n");
   height = 8;

   row=height;
   col=row+1;

   for(r=0;r<row+1;r++) {
      for(c=0;c<col;c++) {
         if(r>0) {
            spaces = col-(r+1);
            if(c<spaces)
               printf("%c",' ');
            else
               printf("%c",'#');
         }
      }
      if(r > 0)
         printf("  row %d\n",r);
   }

   printf("\n");
   return 0;
}