如何在每列增加1的情况下连续循环，依此类推

Question

I have homework to make a program to display several data with the following display:

#
#$
#$%
#$%#
#$%#$
#$%#$%

I had tried, but it looks so weird, I don't know what else to do, I'm stuck, this is my code :

 let str = ''; for (let i = 0; i < 6; i++) { str += '#'; for (let j = 0; j < i; j++) { str += '$'; for (let k = 1; k < i; k++) { str += '%'; for (let k = 1; k < i; k++) { str += '#'; } } } str += backpace = '\\n'; } console.log(str); 

my code does not display what I expect, I hope sombody can help me

Answer 1

You just need two loops, one for the rows, and one for the columns. The loop for the columns only has to iterate to the current row number, eg for the third row, the column loop has to iterate three times.

  for(let col = 0; col <= row; col++)

To get the character to be displayed at a certain column you could take a string of the characters to repeatedly display, eg "#$%" , then access the col-th character in that string. With the modulo operator you can then make sure that col 3 results in the first char to be taken, col 4 the second and so on:

 "#$%"[col % 3] // 0 => "#", 1 => "$", 2 => "%", 3 => "#", ...

Answer 2

Way too many loops, you only need 2 loops

  let dict = ["#", "$", "%"]; // available symbols in order let str = ''; // final string let linesToRender = 6; // number of lines to render for (let line = 0; line < linesToRender ; line++) { // line loop for (let col = 0; col <= line; col++) { // column loop ( from 0 to line number ) str += dict[col % dict.length] } str += "\\n"; } console.log(str); 

Answer 3

Ok here's your homework. Do not use that many loops, it is not necessary. Just store the current line and concat next char in next loopcycle.

 const source = '#$%'; let str = ''; let output = ''; for (let i = 0; i < 6; i++) { str += source[i % source.length]; output += str + '\\n'; } console.log(output);