I thought long and hard before asking this in here but I've spent too much time now trying to figure this one out without cheating.
The CS50 mario ps1 (less comfortable) asks for a *simple left align (at first) pyramid, but my code is giving me it upside down and I can't figure why.
#include <cs50.h>
#include <stdio.h>
int main (void)
{
int n;
do
{
n = get_int("Pyramid Height: ");
}
while (n < 1 || n > 8);
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n - i ; j++)
printf("#");
for (int j = 0; j < n - i; j++)
{
printf(" ");
}
printf("\n");
}
}
I'm sorry if this type of questioning shows up regularly here but I really do need your help.
Thanks in advance.
edit:
expected result:
........#
.......##
......###
.....####
....#####
...######
..#######
.########
I can change the dots to spaces afterwards, this is just for visualisation;
the restriction for height is 8, so I guess that each line has always eight characters;
I actually added trailing spaces so that the pyramid could be right aligned, I've metioned wrong before;
I'm going to check the How to debug small programs?;
Sorry, I'm new to this, I didn't know there was a difference between here and stack exchange, gonna look into that.
*Sorry for the "meh" english, it is not my native language.
See what is the difference between my and your code (especially how to count):
void draw(int n, int align, int dir)
{
for (int i = 1; i <= n; i++)
{
if(align)
{
for(int s = 0; s < (dir ? (n - i) : i - 1); s++)
{
printf(" ");
}
}
for (int j = 0; j < (dir ? i : (n - i + 1)) ; j++)
{
printf("#");
}
printf("\n");
}
}
int main (void)
{
draw(8,1,0);
printf("\n");
draw(8,1,1);
printf("\n");
draw(8,0,0);
printf("\n");
draw(8,0,1);
}
https://godbolt.org/z/7YT16j
my code is giving me it upside down and I can't figure why
Let's see what the code looks like
// There's a loop executed n times. The body prints a line, so n lines are printed.
// In case you have doubts, the characters are normally printed top to bottom and
// left to right.
for (int i = 0; i < n; i++)
{
// The following loop prints (n - i) characters '#' at the beginning
// of each line. That's NOT what you are supposed to do, kind the opposite.
for (int j = 0; j < n - i ; j++)
printf("#");
// You should first print the spaces, then the '#'s, starting from 1 '#' at
// the first line and increasing the number by one at each line (so you have
// to change the condition in the loop accordingly).
// This loop prints the right amount of spaces, but only after
// all the '#'s and just before the end of the line, so that you just
// can't see them (change the printed char to '.' to visualize those).
for (int j = 0; j < n - i; j++)
{
printf(" ");
}
// Note that you could use putchar('\n'), here and previously, to print
// only one char, instead of using printf() to print string literals.
printf("\n");
}
Related
I am working on this problem from the CS50 class. I am still a beginner. What I need to program is this:
Toward the end of World 1-1 in Nintendo’s Super Mario Brothers, Mario
must ascend right-aligned pyramid of blocks, a la the below.
screenshot of Mario jumping up a right-aligned pyramid
Let’s recreate that pyramid in C, albeit in text, using hashes (#) for
bricks, a la the below. Each hash is a bit taller than it is wide, so
the pyramid itself is also be taller than it is wide.
#
##
###
####
#####
######
#######
########
The program we’ll write will be called mario. And let’s allow the user
to decide just how tall the pyramid should be by first prompting them
for a positive integer between, say, 1 and 8, inclusive.
However I have tried many ways, two of which are these:
code mariov1
After looking at some Stack Overflow attempts, it now looks like this:
#include <cs50.h>
#include <stdio.h>
string hash(int);
int main(void)
{
int n;
do
{
n = get_int("Height: ");
}
while (n < 0 || n > 8);
for(int i = 0; i < n; i++)
{
for(int j = 0; j < n-1-i; j++)
{
for(int j = 0; j < i+1; j++)
{
printf(".");
}
printf("#");
}
printf("\n");
}
}
What can I try next?
Suriyu, to add to what Weather Vane said. To pass it through Check50, you'll still need to make small tweaks to the code so that it passes through all CS50 tests.
For the do-while loop, n <=0 instead of n < 0 to ask for an input when n = 0, because the specification demands a minimum of one brick (1 to 8 both inclusive).
You need only the two loops, don't print extra characters not specified in the problem set, ex: printf(".");
All the best with CS50, it's going to be a fun experience!
#include <cs50.h>
#include <stdio.h>
int main(void)
{
int n;
do
{
n = get_int("Height: ");
}
while (n < 1 || n > 8);
// this for loop makes new lines
for (int i = 0; i < n; i++)
{
// here I have two for loops nested inside the above for loop,
// I previously made the mistake of having two inner loops nested.
// this 2nd for loop prints n-1-i spaces
// because if n=5, then in the 4th row, there will be 5-1-3 spaces/dots
for (int j = 0; j < n - 1 - i; j++)
{
printf(" ");
}
// this 3rd for loop prints i+1 hashes
// because if n=5, then in the 4th row, there will be 3+1 hashes.
// (3 because you count from 0)
for (int j = 0; j < i + 1; j++)
{
printf("#");
}
printf("\n");
}
}
#include <cs50.h>
#include <stdio.h>
int main(void)
{
int n;
do
{
n = get_int("Height of the pyramid is:\n");
}
while (n < 1 || n > 8); //condition to get a number from 1-8 from the user
for (int i = 0; i < n; i++) //loop for height
{
for (int j = 0; j < n - 1 - i; j++) //loop for spaces on left pyramid
{
printf(" ");
}
for (int k = 0; k < i + 1; k++) // loop for hashes on left pyramid
{
printf("#");
}
printf(" "); // spacing between pyramids
for (int p = 0; p <= i; p++) //loop for right pyramid
{
printf("#");
}
printf("\n");
}
}
This is the advanced version of the problem if you decide to try it.
Here's a different approach. Instead of iteratively printing blanks, followed by iteratively printing number signs, this version creates a buffer (size defined by a precompiler constant - currently set to 8, change it if you want to allow bigger pyramids), then for each row in the pyramid it first fills the buffer with number signs, then overlays the beginning of the line with the proper number of spaces, and then prints it:
#include <cs50.h>
#include <stdio.h>
#include <string.h>
#define MAXSIZE 8
int main(void)
{
int size, spaces;
char buf[MAXSIZE+1];
do
size = get_int("Height: ");
while (size < 0 || size > MAXSIZE);
buf[size] = '\0';
for(spaces = size-1 ; spaces >= 0 ; --spaces)
printf("%s\n", (char *)memset(memset(buf, '#', size), ' ', spaces));
}
EDIT
And here's yet another approach which builds the entire output block in an array in memory and then prints it using a single call to puts:
#include <cs50.h>
#include <stdio.h>
#include <string.h>
#define MAXSIZE 8
#define TOTSIZE ((MAXSIZE+1) * MAXSIZE)
int main(void)
{
int size, spaces;
char buf[TOTSIZE+1];
do
size = get_int("Height: ");
while (size < 0 || size > MAXSIZE);
memset(buf, '\n', (size+1)*size);
buf[((size+1)*size)] = '\0';
for(char *p = buf, spaces = size-1 ; *p != '\0' ; p += size+1, --spaces)
memset(memset(p, '#', size), ' ', spaces);
puts(buf);
}
This is an option that likely works best:
from cs50 import get_int
while True:
n=get_int("Enter Height: ")
if n>=1 and n<=8:
break
for i in range(0, n-1):
print(" " * (n - (i+1)) + "#" * (i+1))
This is my current code
void printer(int input)
{
int star;
int space;
for (int i = 1; i <= input; i++)
{
star = i;
space = i + input - star - 1;
for (int j = 0; j < space; j++)
{
printf(" ");
}
for (int s = 0; s < star; s++)
{
printf("*");
}
printf("\n");
}
}
I'm trying to print it out like
How tall 3?
*
* *
* * *
_| |_
\___/
and this is what i get. What is wrong with my code? and how will I fix the code?
How Tall? 3
*
**
***
Essentially, this snippet of code here that you use:
star = i;
space = i + input - star - 1; // or, space = input - 1 + i - star;
is the same as writing:
star = i;
space = input - 1;
This is because i and star have the same value (quoth star = i), and therefore, negate each other.
Now, can you see a constant here? Yes, the value of input is never changed anywhere, and therefore your code is always what 1 less than the input is. (In this case, its always preceded by 2 (=3-1) spaces) like this:
*
**
***
^^ mark two spaces
And you also forgot to add a trailing space after the asterix and hence there is no spacing between them.
Therefore, to solve your problem, you could store the value of input temporarily and reduce it by 1 in every iteration so it appears like a pyramid.
Example:
void printer(int input)
{
int star;
int space;
// Store the original length of the space
int space_length = input;
for (int i = 1; i <= input; i++)
{
star = i;
// Get the number of spaces for the current iteration
space = space_length - 1;
for (int j = 0; j < space; j++) {
printf(" ");
}
for (int s = 0; s < star; s++) {
printf("* ");
// ^ note this space after the asterisk
}
// Decrease the length of the space every step
// So that it appears like a slope
// Note how we are using 'space_length' instead of input
// This is because if we decrement 'input', this loop
// will get affected, which is not what we want
space_length--;
printf("\n");
}
///////// bottom part of the tree /////////
// number of spaces needed = input - length of "_| |_" - 1
for (int i = 1; i <= input - (4 - 1); i++)
printf(" ");
printf("_| |_\n");
// number of spaces needed = input - length of "\\___/" - 1
for (int i = 1; i <= input - (4 - 1); i++)
printf(" ");
printf("\\___/\n");
}
which gives the output:
*
* *
* * *
_| |_
\___/
your format is the issue. as you already know the size of the tree, you can deduct the size of the first set of whitespace (the first spaces on each lines), being spaces = (size - 1) - i. it should be, for each i:
i1 = 2
i2 = 1
i3 = 0
which seems to be what the result gives. additionally, between all asterix, just insert one space until the last character, and that's the idea
There are too many things gone wrong with this. I'll not post the correct code, but can guide you through it.
Since you want space after stars, print "* " instead of "*"
You have to use decremental space in beginning, before printing star, there's some logical fault in that, which is, you are adding and subtracting i and star, which are same thing. You need to give (input - star) spaces for the loop.
For the trunk, you have to develop some symmetrical logic.
I hope it helps you.
You can do it like this:
#include <stdio.h>
void printer(int input)
{
// for stars
for (int i = 1; i <= input; i++) {
for (int j = 1; j <= input - i; j++) {
printf(" ");
}
for (int k = 1; k <= i; k++) {
if (k == 1) printf("*");
else printf(" *");
}
printf("\n");
}
// for base
int base_half_len = input - 1;
for (int i = 1; i < base_half_len; i++) {
printf("_");
}
printf("| |");
for (int i = 1; i < base_half_len; i++) {
printf("_");
}
printf("\n\\");
for (int i = 1; i < 2 * input - 2; i++) {
printf("_");
}
printf("/\n");
}
int main(void) {
// your code goes here
printer(10);
return 0;
}
Here's the link where I tested it: https://ideone.com/7zpNeW
When I print out a pyramid, the last line of the pyramid or the base prints out an integer which represents how many hashes, instead of a string of hashes.
like such:
Height: 3
#
##
3
when its supposed to be:
Height 3:
#
##
###
I'm supposed to print out a pyramid with a height based on the user's input, but instead of the base being printed out as a string it prints out an integer of how many hashes there should be for the base. I understand that this is because I'm returning n but I don't know how to go about it in a way where it still returns the loop.
I've tried changing the class to void instead of int, but that throws an error as it's conflicting types. I'm thinking I should print out an empty string but it messes with my bounds.
#include <cs50.h>
#include <stdio.h>
int get_height(string prompt);
int main(void)
{
int ask = get_height("Height: ");
printf("%i\n", ask);
}
int get_height(string prompt) {
int n;
do {
n = get_int("%s", prompt);
}
while (n < 1 || n > 8);
for (int i = 0; i < n; i++) {
for (int j = 0; j < i; j++) {
printf("#");
}
printf("\n");
}
return n;
}
The last line of output is the height because that is the last thing printed in your main function:
printf("%i\n", ask);
get_height will actually only print n-1 lines because the first iteration (i=0,j=0) is skipped.
the 3 should be output
The problem is this statement;
for (int j = 0; j < i; j++) {
which stops too early. Suggest:
for (int j = i; j >=0; j--) {
The output after making the above change:
#
##
###
3
I was working though some beginning problem sets with Harvard's online CS50 class. I got the problem to work correctly but I was wondering if there would possibly be a cleaner or better way to get the program to work.
The goal of the program is to print a right-aligned pyramid comprised of hash-tags and space characters. Any guidance in regards to style or tricks would be very welcome.
/* Creating the mario program, whose goal is to create a
* pyramid by accepting input from the user to get the
* height then aligning the pyrimid to the right.
*
*/
#include <stdio.h>
#include <cs50.h>
int main(void)
{
// get user input and set to variable
printf("Height: ");
int height = GetInt();
int i, j, k;
for(i = 1 ; i < height; i++)
{
// create n-1 spaces
for(k = (height - 2); k > (i-1); k--)
{
printf("%c", ' ');
}
// create n+1 hash tags
for(j = 0; j < (i+1); j++)
{
printf("#");
}
printf("\n");
}
return 0;
}
I'm assuming by cleaner you mean "spiffy and fancyer".
This looks spiffy to me:
#include <stdio.h>
#include <cs50.h>
int main(void) {
// get user input and set to variable
printf("Height: ");
int height = GetInt();
int hm2 = height - 2;
int j, k;
for(int i = 1 ; i < height; i++) {
// create n-1 spaces
for(k = hm2; k > (i-1); k--)
printf("%c", ' ');
// create n+1 hash tags
for(j = 0; j < (i+1); j++)
printf("#");
printf("\n");
}
return 0;
}
However, don't get too caught up in making your code fancy. Although it's nice if you're working with others, or yourself really. Your example looked fine.
Now, optimization-wise, that's something to worry about. Just remember that too much optimization can potentially break your program.
For everyone's consideration: this is what "all style and no readability" looks like :)
i = 0;
while (i++ < height*height)
printf ("%c%s", (i-1)/height < height-(i-1)%height-1 ? ' ' : '#',
i % height ? "" : "\n");
It is nigh on impossible to see what the code does without running it. If there is to be a follow-up exercise, this is hard to re-write to form, say, an even-sided pyramid. I'd probably throw this away and start again with the basics, before concatenating it again into a little monster such as this.
(later) Ever so slightly more neat to put the i++ at the end, so two times (i-1) gets traded for a slightly more complicated end-of-line test:
i = 0;
do
printf ("%c%s", i/height < height-i%height-1 ? ' ' : '#',
i % height==height-1 ? "\n" : "");
while (++i < height*height);
I think by cleaner and better way you mean to be a perfect shaped right angled triangle pyramid.
For this you should do as
Change
printf("Height: ");
to
printf("Height: \n\n");
and
for(i = 1 ; i < height; i++)
to
for(i = 0 ; i < height; i++)
And see the sample output.
Here's a suggestion:
#include <stdio.h>
#include <cs50.h>
int main(void) {
//initialize variables
int height, hm2, j, k, i;
printf("Height: \n");
// Get user input
height = GetInt();
hm2 = height - 1;
for(i = 0; i < height; i++) {
// create n spaces
for(k = hm2; k > i; k--)
printf("%c", ' ');
// create n+1 hash tags
for(j = 0; j < i+1; j++)
printf("#");
printf("\n");
}
return 0;
}
Result if the user entered a 5 for the height:
Height:
#
##
###
####
#####
A couple things I considered with this version of the code:
-In C, it's good practice to declare all variables separately from giving them a value and assign values later. Some compilers may bring up this error if you to declare and assign a value in a for loop: "error: ‘for’ loop initial declarations are only allowed in C99 mode". These changes are considered with what I have provided.
//initialize variables
int height, hm2, j, k, i;
-I added a newline here
printf("Height: \n");
-Instead of hm2 = height - 2 I changed it to:
hm2 = height - 1;
-First loop, now we give i a value and set it to 0 to meet the other changes that were made:
for(i = 0; i < height; i++) {
-For the loop creating n spaces I changed it to:
for(k = hm2; k > i; k--)
-Finally removed parenthesis (no need in this case) in last for loop:
for(j = 0; j < i+1; j++)
Cheers
Code1:
#include<stdio.h>
int main()
{
unsigned short i, j, k;
for (i = 0; i < 2; i++)
{
k = i * 4 + 4;
for (j = k - 4; j < k; j++)
printf("%hu ", j);
putchar('\n');
}
return 0;
}
Output of Code1:
0 1 2 3
4 5 6 7
Remarks of Code1:
Space after 3 and 7
Newline after 7 (Stackoverflow has removed it)
Code2:
#include<stdio.h>
int main()
{
unsigned short i, j, k;
for (i = 0; i < 2; i++)
{
k = i * 4 + 4;
for (j = k - 4; j < k; j++)
{
printf("%hu", j);
if (j + 1 != k) putchar(' ');
}
if (i + 1 != 2) putchar('\n');
}
return 0;
}
Output of Code2:
0 1 2 3
4 5 6 7
Remarks of Code2:
No space after 3 and 7
No newline after 7
Additional remark of Code2:
The problem of Code2 is that the algorithm always compares two values in the if blocks and so Code2 is not efficient. I want to use Code1 and change these:
Code3
#include<stdio.h>
int main()
{
unsigned short i, j, k;
for (i = 0; i < 2; i++)
{
k = i * 4 + 4;
for (j = k - 4; j < k; j++)
printf("%hu ", j);
printf("\b\n");
}
putchar('\b');
return 0;
}
These do not show the same output of Code2 because \b does not erase anything.
My question:
Is there any standard way to do so what I've tried in Code3?
Remark of my question:
I have searched the internet but have not determined the solution.
Edit the question if it is not clear.
Edit: I don't know why my question is not useful or constructive. Though the above is an arbitrary small example, but performance might be an issue when processing very large amount of data. I thought that the way of removing character from console output might improve performance and there might be a specific way to do so. That's why I've asked the question. I could write the following codes in the answers. Now I've known via comments that removing character from console output is not possible because it is implementation dependent.
The usual approach to this is to treat either the first or the last printf as a special case (outside of the loop):
for(ii=0; ii<2; ii++) {
jj = 0;
printf("%d", jj); // first number printed without space.
for(jj=1; jj<4; jj++) {
printf(" %d", jj); // include the space before the number printed
}
if(ii<2-1) printf("\n");
}
Obviously I simplified how the loops are constructed and what is printed - for simplicity. You could make the first printf statement
printf("\n%d", jj);
then you have a newline at the start of your output (often a good thing) and then you don't need the if statement later - you just don't have a newline printed at the end of the line (because it will be printed at the start...)
There are marginally more efficient ways of doing this that would involve no if statements at all - but these all come at the expense of less readable code. For example, here is a "no loop unrolling and no additional if statements" version of the code:
http://codepad.org/01qPPtee
#include <stdio.h>
int main(void) {
int ii, jj;
ii = 0;
while(1) {
jj = 0;
while(1) {
printf("%d", jj); // include the space before the number printed
jj++;
if(jj<4) printf("."); else break;
}
ii++;
if(ii<2) printf("*\n"); else break;
}
return 0;
}
Output:
0.1.2.3*
0.1.2.3
Basically I have taken the functionality of the for loop and made it explicit; I also use a . rather than a and "*\n" rather than "\n" to show in the printout that things behave as expected.
It does what you asked without extra evaluation of the condition. Is it more readable? Not really...
If it really bothers you, you can unroll your loops a little so that you treat the last item as a special case:
#include<stdio.h>
int main()
{
unsigned short i, j, k;
for (i = 0; i < 1; i++)
{
k = i * 4 + 4;
for (j = k - 4; j < k - 1; j++)
{
printf("%hu ", j);
}
printf("%hu\n", j);
}
k = i * 4 + 4;
for (j = k - 4; j < k - 1; j++)
{
printf("%hu ", j);
}
printf("%hu", j);
return 0;
}
#include <stdio.h>
int main(){
unsigned short num = 0, to=8;
while(num < to){
printf("%hu", num++);
if(num < to)
putchar(num % 4 == 0 ? '\n' : ' ');
}
#if 0
do{
printf("%hu", num++);
}while(num < to && putchar(num % 4 == 0 ? '\n' : ' '));
#endif
return 0 ;
}
Well, to try to answer your question, here's how I would do it:
for (i = k = 0; i < 2; i++){
if (i > 0) printf("\n");
for (j = 0; j < 4; j++, k++){
if (j > 0) printf(" ");
printf("%d", k);
}
}
I do it this way because I want to be sure every line but the first starts with a \n, and every item is separated by a space from the one before it.
Also, I do not want the row and column position to be intimately tied to the content of what is being printed.
In terms of performance, keep in mind that these if statements cost about 1 cycle, while each character printed costs at least hundreds if not thousands. printf goes through many layers of system calls to interpret its format string, build a buffer, send the buffer to the system I/O routines, which then cause repainting and scrolling of the console window. Get the idea?
DO NOT WORRY about performance unless you know you have a problem.
Then, don't guess. Use a diagnostic. Here's what I do.