How can I multiply a string in the C language?

Question

I want to "multiply" a string by an int variable that the user inputs.

#include <cs50.h>
#include <stdio.h>

    // Height < 24

    string block = "#";
    string output;

    int main(void) {
        printf("Height: ");
        int height = GetInt();
        while (true) { 
            if (height < 24 && height > 0) {
                output = "#" + block * height;
                printf("%s\n", output); 
                break;

            } else {
                printf("Height: ");
                height = GetInt();
            }
        }
        return 0;
    }

Using the Height variable I want to multiply the string variable block (#) by Height, and add that to another "#".

I tried implementing it in the only way I could think of it making sense however it doesnt seem the syntax is right.

I've looked over StackOverflow on this subject and can only find C# and C++ topics with this question in mind.

EDIT: After being printed the output should look like this:

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

And the lines of "#" being outputted depends on the Height variable that the user inputs. Say the user inputs a height of "5":

Height: 5
       ##
      ###
     ####
    #####
   ######

Should be output.

Solution 1

So you need 2 loops to do this. One for iterating through the characters you want to print on a line, one to iterate through the entire height (number of lines).

So what we want to do is:

• Go through each line from 1 up to and including the height.
• For each line, output as many #'s as the current line number

e.g.

 int lineno;
 int height  = GetInt();
 ... 
 for (lineno = 1; lineno <= height; lineno++) {
      int column;
      for (column = 0; column < lineno; column++) {
           putchar('#');
      }
     putchar('\n');
 }

This will be a left adjusted tree. I'll leave it up to you to right adjust it, i.e. print spaces in front of the '#', or start by printing 2 #'s instead of 1.

Solution 2

You don't multiply a string, you simply use a loop and output the character repeatedly.

int j;
for (j = 0; j < (1 + height); ++j) {
    printf ("#");  /* Or putchar('#') */
}
printf ("\n");

Comments

[Peter - Reinstate Monica]

This will segfault with a probability of about 1-1E-6.