Create 12 alphabet patterns in javascript
Tags: javascript, programming
Published: 2020-11-26 03:36:00

**Practice makes a man perfect!**
Let's create a few interesting alphabet patterns in javascript and understand loop in a better way.

## What is alphabet patterns?
Alphabet patterns are a series of alphabets (Uppercase or Lowercase) which create some shape or geometrical figure.
Creating **[alphabet patterns](https://www.tutorialstonight.com/js/javascript-alphabet-pattern)** or **[star patterns](https://www.tutorialstonight.com/js/javascript-star-pattern)** helps us to understand how to use and control loops.
Pattern questions are also asked in a freshers programming interview.
For explanation with real-time running code, [check the article](https://www.tutorialstonight.com/js/javascript-alphabet-pattern).

### Pattern 1:
>A
>A B
>A B C
>A B C D
>A B C D E

```javascript
let n = 5; // you can take input from prompt or change the value
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  // printing characters
  for (let j = 0; j < i; j++) {
    string += String.fromCharCode(j + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 2:
>A
>B B
>C C C
>D D D D
>E E E E E

```javascript
let n = 5; // you can take input from prompt or change the value
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  // printing characters
  for (let j = 0; j < i; j++) {
    string += String.fromCharCode((i - 1) + 65);
  }
  string += "\n";
}
console.log(string);
```


### Pattern 3:
>A
>B C
>D E F
>G H I J
>K L M N O

```javascript
let n = 5;
let string = "";
let count = 0;
// External loop
for (let i = 1; i <= n; i++) {
  for (let j = 0; j < i; j++) {
    string += String.fromCharCode(count + 65);
    count++; // increment cause next alphabet
  }
  string += "\n";
}
console.log(string);
```

### Pattern 4:
>ABCDE
>ABCD
>ABC
>AB
>A

```javascript
let n = 5;
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  for (let j = 0; j < n - i + 1; j++) {
    string += String.fromCharCode(j + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 5:
>EDCBA
>EDCB
>EDC
>ED
>E

```javascript
let n = 5;
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  for (let j = 0; j < n - i + 1; j++) {
    string += String.fromCharCode((n - 1 - j) + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 6:
>EDCBA
>DCBA
>CBA
>BA
>A

```javascript
let n = 5;
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  for (let j = 0; j < n - i + 1; j++) {
    string += String.fromCharCode((n - i - j) + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 7:
>    A
>   ABC
>  ABCDE
> ABCDEFG
>ABCDEFGHI

```javascript
let n = 5;
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  // creating spaces
  for (let j = 0; j < n - i; j++) {
    string += " ";
  }
  // creating alphabets
  for (let k = 0; k < 2 * i - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 8:
>    A
>   BCD
>  EFGHI
> JKLMNOP
>QRSTUVWXY

```javascript
let n = 5;
let string = "";
let count = 0;
// External loop
for (let i = 1; i <= n; i++) {
  // creating spaces
  for (let j = 0; j < n - i; j++) {
    string += " ";
  }
  // creating alphabets
  for (let k = 0; k < 2 * i - 1; k++) {
    string += String.fromCharCode(count + 65);
    count++;
  }
  string += "\n";
}
console.log(string);
```

### Pattern 9:
>ABCDEFGHI
> ABCDEFG
>  ABCDE
>   ABC
>    A

```javascript
let n = 5;
let string = "";
// External loop
for (let i = 1; i <= n; i++) {
  // creating spaces
  for (let j = 1; j < i; j++) {
    string += " ";
  }
  // creating alphabets
  for (let k = 0; k < 2 * (n - i + 1) - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 10:
>    A
>   ABC
>  ABCDE
> ABCDEFG
>ABCDEFGHI
> ABCDEFG
>  ABCDE
>   ABC
>    A

```javascript
let n = 5;
let string = "";
// Pyramid
for (let i = 1; i <= n; i++) {
  for (let j = 1; j < n - i + 1; j++) {
    string += " ";
  }
  for (let k = 0; k < 2 * i - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
// Reverse Pyramid
for (let i = 1; i <= n - 1; i++) {
  for (let j = 1; j < i + 1; j++) {
    string += " ";
  }
  for (let k = 0; k < 2 * (n - i) - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 11:
>ABCDEFGHI
> ABCDEFG
>  ABCDE
>  ABC
>    A
>   ABC
>  ABCDE
> ABCDEFG
>ABCDEFGHI

```javascript
let n = 5;
let string = "";
// Reverse Pyramid
for (let i = 1; i <= n; i++) {
  for (let j = 1; j < i; j++) {
    string += " ";
  }
  for (let k = 0; k < 2 * (n - i + 1) - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
// Pyramid
for (let i = 1; i <= n - 1; i++) {
  for (let j = 1; j < n - i; j++) {
    string += " ";
  }
  for (let k = 0; k < 2 * (i + 1) - 1; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
console.log(string);
```

### Pattern 12:
>A
>AB
>ABC
>ABCD
>ABCDE
>ABCD
>ABC
>AB
>A

```javascript
let n = 5;
let string = "";
// Pyramid
for (let i = 1; i <= n; i++) {
  for (let k = 0; k < i; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
// Reverse Pyramid
for (let i = 1; i <= n - 1; i++) {
  for (let k = 0; k < n - i; k++) {
    string += String.fromCharCode(k + 65);
  }
  string += "\n";
}
console.log(string);
```