# String Formatting

This Go code demonstrates the usage of the `fmt` package for formatted printing and string formatting. Let's go through the code with inline comments and explanations:

```go
// Importing necessary packages.
import (
	"fmt"
	"os"
)

// Defining a custom type 'point' with two integer fields.
type point struct {
	x, y int
}

// The main function, where the execution of the program begins.
func main() {
	// Creating an instance of the 'point' struct.
	p := point{1, 2}

	// Printing the struct 'p' using different format specifiers.
	fmt.Printf("struct1: %v\n", p)    // Default format.
	fmt.Printf("struct2: %+v\n", p)   // Adds field names.
	fmt.Printf("struct3: %#v\n", p)   // Adds Go syntax representation.

	// Printing the type of 'p'.
	fmt.Printf("type: %T\n", p)

	// Printing a boolean value.
	fmt.Printf("bool: %t\n", true)

	// Printing an integer value.
	fmt.Printf("int: %d\n", 123)

	// Printing an integer in binary format.
	fmt.Printf("bin: %b\n", 14)

	// Printing a character using its ASCII value.
	fmt.Printf("char: %c\n", 33)

	// Printing an integer in hexadecimal format.
	fmt.Printf("hex: %x\n", 456)

	// Printing a floating-point number.
	fmt.Printf("float1: %f\n", 78.9)

	// Printing a floating-point number in scientific notation.
	fmt.Printf("float2: %e\n", 123400000.0)
	fmt.Printf("float3: %E\n", 123400000.0)

	// Printing a string.
	fmt.Printf("str1: %s\n", "\"string\"")

	// Printing a string with double quotes.
	fmt.Printf("str2: %q\n", "\"string\"")

	// Printing a string in hexadecimal format.
	fmt.Printf("str3: %x\n", "hex this")

	// Printing a pointer value.
	fmt.Printf("pointer: %p\n", &p)

	// Printing integers with specified width.
	fmt.Printf("width1: |%6d|%6d|\n", 12, 345)

	// Printing floating-point numbers with specified width and precision.
	fmt.Printf("width2: |%6.2f|%6.2f|\n", 1.2, 3.45)

	// Printing floating-point numbers with specified width and left alignment.
	fmt.Printf("width3: |%-6.2f|%-6.2f|\n", 1.2, 3.45)

	// Printing strings with specified width.
	fmt.Printf("width4: |%6s|%6s|\n", "foo", "b")

	// Printing strings with specified width and left alignment.
	fmt.Printf("width5: |%-6s|%-6s|\n", "foo", "b")

	// Using Sprintf to format a string.
	s := fmt.Sprintf("sprintf: a %s", "string")
	fmt.Println(s)

	// Using Fprintf to format and print a string to os.Stderr.
	fmt.Fprintf(os.Stderr, "io: an %s\n", "error")
}
```

#### output

```
struct1: {1 2}
struct2: {x:1 y:2}
struct3: main.point{x:1, y:2}
type: main.point
bool: true
int: 123
bin: 1110
char: !
hex: 1c8
float1: 78.900000
float2: 1.234000e+08
float3: 1.234000E+08
str1: "string"
str2: "\"string\""
str3: 6865782074686973
pointer: 0xc00000a0d0
width1: |    12|   345|
width2: |  1.20|  3.45|
width3: |1.20  |3.45  |
width4: |   foo|     b|
width5: |foo   |b     |
sprintf: a string
io: an error
```

Explanation:

1. **Printing Structs:**
   * `struct1`, `struct2`, and `struct3` showcase different ways to print a struct (`point` in this case) with various formatting options.
2. **Printing Types:**
   * `%T` is used to print the type of a value.
3. **Printing Booleans and Integers:**
   * `%t` is used for boolean values.
   * `%d` is used for decimal integers.
4. **Printing Binary, Character, and Hexadecimal:**
   * `%b` prints integers in binary format.
   * `%c` prints a character using its ASCII value.
   * `%x` prints integers in hexadecimal format.
5. **Printing Floating-Point Numbers:**
   * `%f` prints floating-point numbers.
   * `%e` and `%E` print floating-point numbers in scientific notation.
6. **Printing Strings:**
   * `%s` prints strings.
   * `%q` prints strings with double quotes.
   * `%x` prints strings in hexadecimal format.
7. **Printing Pointers:**
   * `%p` is used to print pointer values.
8. **Printing with Width and Alignment:**
   * Various examples demonstrate printing with specified width and alignment using `%6d`, `%6.2f`, `%-6.2f`, `%6s`, and `%-6s`.
9. **String Formatting with Sprintf:**
   * `Sprintf` is used to format a string without printing it to the console.
10. **Printing to os.Stderr:**
    * `Fprintf` is used to format and print a string to `os.Stderr`.

This code provides a comprehensive overview of the formatting options available in the `fmt` package for various types of values.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://ineelhere.gitbook.io/code-with-go/49-string-formatting.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.