Start Coding

Subjects

JAVASCRIPTHTMLCSSPYTHONSQLJAVACPPCSHARPPHPTYPESCRIPTCRUBYGOSWIFTKOTLINRUSTRBASHSCALAOBJECTIVE-CDARTPERLLUAMATLABXMLJSONMARKDOWNASSEMBLYLATEXYAMLSOLIDITYBLOCKCHAIN

Topics

Go Basics

Introduction to GoInstalling GoGo SyntaxGo VariablesGo Data TypesGo ConstantsGo OperatorsGo CommentsGo KeywordsGo IdentifiersGo PackagesGo Import StatementGo Main FunctionGo Print Functions

Control Structures

Go If-Else StatementsGo Switch StatementGo For LoopGo RangeGo Break and ContinueGo DeferGo Panic and Recover

Functions

Go Function DeclarationGo Function ParametersGo Return ValuesGo Multiple Return ValuesGo Named Return ValuesGo Variadic FunctionsGo Anonymous FunctionsGo ClosuresGo Recursion

Data Structures

Go ArraysGo SlicesGo MapsGo StructsGo PointersGo Type AssertionsGo Type Switches

Object-Oriented Programming

Go MethodsGo InterfacesGo EmbeddingGo CompositionGo Polymorphism

Concurrency

Go GoroutinesGo ChannelsGo Select StatementGo Buffered ChannelsGo Channel SynchronizationGo Channel DirectionsGo WaitGroupsGo MutexesGo Atomic Operations

Error Handling

Go Error InterfaceGo Creating Custom ErrorsGo Error WrappingGo Error Handling Best Practices

File Handling

Go File OperationsGo Reading FilesGo Writing FilesGo File Permissions

Testing

Go Testing PackageGo Unit TestingGo Benchmark TestingGo Test CoverageGo Table-Driven Tests

Standard Library

Go fmt PackageGo io PackageGo os PackageGo strings PackageGo time PackageGo math PackageGo sort PackageGo encoding/json PackageGo net/http Package

Advanced Topics

Go ReflectionGo ContextGo GenericsGo Memory ManagementGo Garbage CollectionGo Race DetectorGo AssemblyGo cgoGo ProfilingGo Cross-Compilation

Best Practices

Go Code OrganizationGo Error Handling PatternsGo Naming ConventionsGo DocumentationGo Performance OptimizationGo Idiomatic GoGo Project Structure

Tools and Ecosystem

Go ModulesGo WorkspacesGo Command-Line ToolsGo LintersGo FormattersGo Dependency ManagementGo Build TagsGo Generate

The fmt Package in Go

The fmt package is a core component of Go's standard library. It provides essential functionality for formatted I/O operations, making it indispensable for most Go programs.

Purpose and Functionality

The fmt package serves two primary purposes:

  1. Formatting output for console and file writing
  2. Parsing formatted input from various sources

It offers a wide range of functions for printing, scanning, and string manipulation, making it a versatile tool for Go developers.

Common Functions

Printing Functions

  • fmt.Print(): Prints arguments to standard output
  • fmt.Println(): Prints arguments followed by a newline
  • fmt.Printf(): Prints formatted output

Scanning Functions

  • fmt.Scan(): Scans text from standard input
  • fmt.Scanf(): Scans formatted text from standard input

Practical Examples

Basic Printing


package main

import "fmt"

func main() {
    name := "Alice"
    age := 30
    fmt.Printf("Hello, %s! You are %d years old.\n", name, age)
}

This example demonstrates the use of fmt.Printf() for formatted output. The %s and %d are format specifiers for string and integer values, respectively.

Scanning Input


package main

import "fmt"

func main() {
    var name string
    var age int
    fmt.Print("Enter your name and age: ")
    fmt.Scan(&name, &age)
    fmt.Printf("Hello, %s! You are %d years old.\n", name, age)
}

This example shows how to use fmt.Scan() to read user input. The & operator is used to pass pointers to the variables, allowing Scan() to modify their values.

Best Practices

  • Use fmt.Println() for simple, unformatted output
  • Prefer fmt.Printf() when you need precise control over output formatting
  • Always check for errors when using scanning functions
  • Use appropriate format specifiers to ensure type safety

Related Concepts

To deepen your understanding of Go's I/O capabilities, explore these related topics:

The fmt package is a cornerstone of Go programming, essential for both beginners and experienced developers. By mastering its functions, you'll greatly enhance your ability to create robust and user-friendly Go applications.