Function is looping infinitely - do/while functions

Question

Goal:

Implement a program that prints out a double half-pyramid of a specified height, per the below.

$ ./mario
Height: 4
   #  #
  ##  ##
 ###  ###
####  ####

Problem:

Have been messing with the code for the past 3 hours or so. I got the first line to work, but everything beyond that was just 2 parallel pillars consisting of a singular hash mark. At present, the program is indefinitely printing a hash mark.

Code:

int main (void) {
    // user gives height value for pyramid
    // h = height
    int h;
    do {
        printf (
            "How tall do you want your pyramid to be? Please type a number "
            "between 0 and 23.\n");
        h = get_int ();

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

    // Left side of pyramid says spaces first, followed by hashes. Two spaces
    // inbetween sides of the pyramid. Right side renders hashes first, then
    // inputs newline character.
    // r = row
    // s = space
    // p = hash
    // q = hash right
    int q;
    int p;
    int s;
    int r;
    for (r = 0; r < h; r++) {
        do {
            do {
                printf (" ");
                s++;
            } while (s < h - r);

            // says spaces

            do {
                printf ("#");
                p++;
            } while (p < r++);

            // says left hashes

            // always print 2 spaces inbetween
            printf ("  "); // two spaces

            do {
                printf ("#");
                q++;
            } while (q < r++);
            // says right hashes

            printf ("\n");
            q = 0;
            p = 0;
            s = 0;
            // reset q,p,s values

        } // end bracket of encompassing 'do' function
        while (r < h);
        //'for' function should execute once, increment 'r' by 1, and repeat
        //until row height becomes height provided by user.

    } // end bracket of for loop

} // end bracket of int main

Expected Result:

Program creates pyramid formed by hash symbols and spaces.

Actual Result:

Infinitely looping print function.

Answer 1

A shorter implementation, for your study

int i,j;
for (i=0 ; i<h ; i++) {            // h lines
    for(j=0 ; j < h+2+i+1 ; j++) { // cover all characters on 1 line
        printf("%s", j<h-i-1 || j<h+2 && j>=h ? " " : "#");
    }
    printf("\n");                  // end of line
}

Regarding j<h-i-1 || j<h+2 && j>=h ? " " : "#"

• j<h-i-1 spaces before the first #
• j<h+2 && j>=h spaces between the #s
• ?: operator: C ? A : B translates to if C is true give A otherwise give B

Answer 2

the end of your loop is like:

 p++;
}
while (p < r++);

so r is always ahead of p because you're incrementing both. That's your infinite loop.

I get a pretty good result moving r++ after the second while inner loop, like this:

   #  #
  #  #
 ##  ##
###  ###

so still a bit of tuning and you're here. The other issue is with do/while which execute once even if the condition is false. Replace by while loops or you're one off like above:

    do
    {
        while (s < h - r)
        {
            printf(" ");
            s++;
        }
        //says spaces

        while (p < r)
        {
            printf("#");
            p++;
        }

        //says left hashes

        //always print 2 spaces inbetween
        printf("  ");

        //two spaces

        while(q < r)
        {
            printf("#");
            q++;
        }

        //says right hashes
        r++;
        printf("\n");
        q = 0;
        p = 0;
        s = 0;
        // reset q,p,s values

    }//end bracket of encompassing 'do' function
    while(r < h);

Note that it's also cheap to autoindent your code using "Notepad++ / TextFX / TextFX edit / Reindent C++ code"

         #  #
        ##  ##
       ###  ###
      ####  ####
     #####  #####
    ######  ######
   #######  #######
  ########  ########
 #########  #########