Stage 1 · Code

Variables, Types & Control Flow

Operators & Expressions

Combine values with arithmetic, comparison, logical, and string operators — and avoid the integer division trap.

6 min readProgramming Foundations (Go)Code

Arithmetic Operators

Go supports the standard arithmetic operators for numeric types. A key rule: all operands must be the same type. You cannot add an int and a float64 without converting one first.

Goarithmetic-in-go.go

23 linesLn 1, Col 1Go

`a / b` when both are integers divides and **discards the remainder**. `17 / 5` is `3`, not `3.4`. To get the fractional result, convert to `float64` first.

Integer division silently truncates

This is a common beginner mistake. 10 / 3 is 3, not 3.33. If you need the real division, convert at least one operand: float64(10) / float64(3) or 10.0 / 3.0.

Gocompound-assignment-operators.go

18 linesLn 1, Col 1Go

Compound assignment operators (`+=`, `-=`, `*=`, `/=`, `%=`) combine an operation with assignment. They are a shorthand only; there is no `++` or `--` as part of an expression in Go.

Comparison Operators

Comparison operators compare two values of the same type and always return a bool. You cannot use == between two values of different types without an explicit conversion.

Operator	Meaning	Example
==	Equal to	`5 == 5` → true
!=	Not equal to	`5 != 3` → true
<	Less than	`3 < 5` → true
<=	Less than or equal	`5 <= 5` → true
>	Greater than	`7 > 3` → true
>=	Greater than or equal	`3 >= 7` → false

Gousing-comparison-results.go

18 linesLn 1, Col 1Go

Comparison results are just `bool` values. You can store them in variables, pass them to functions, or use them directly in `if` conditions.

Logical Operators

Logical operators combine boolean expressions. && is AND, || is OR, ! is NOT. Both && and || short-circuit: if the result is determined by the left operand, the right operand is never evaluated.

Gological-operators-and-short-circuit-evaluation.go

28 linesLn 1, Col 1Go

Short-circuit evaluation is not just an optimization: it means the right side of `&&` only runs when the left side is `true`. This matters when the right side has a side effect or could panic.

String Operators

Go strings support + for concatenation and all six comparison operators. For building strings in a loop or from many parts, prefer strings.Builder or fmt.Sprintf over repeated +.

Gostring-operations.go

27 linesLn 1, Col 1Go

String `+` creates a new string each time. When building strings in a loop with many iterations, `strings.Builder` is dramatically faster because it amortizes allocations.

Operator Precedence

Go operators have a defined precedence order — similar to standard algebra. Multiplication and division bind tighter than addition and subtraction. When in doubt, use parentheses to make order explicit.

Goprecedence-and-parentheses.go

21 linesLn 1, Col 1Go

Add parentheses whenever the expression mixes `&&` and `||`. It prevents subtle logic bugs and makes the code immediately readable to other engineers.

When in doubt, parenthesize

Operator precedence rules can surprise even experienced developers. Explicit parentheses cost nothing in performance and document your intent clearly. A compiler optimizes them away; a reader relies on them.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.

Stage 1 · Code

Variables, Types & Control Flow

Operators & Expressions

Combine values with arithmetic, comparison, logical, and string operators — and avoid the integer division trap.

6 min readProgramming Foundations (Go)Code

Arithmetic Operators

Go supports the standard arithmetic operators for numeric types. A key rule: all operands must be the same type. You cannot add an int and a float64 without converting one first.

Goarithmetic-in-go.go

23 linesLn 1, Col 1Go

`a / b` when both are integers divides and **discards the remainder**. `17 / 5` is `3`, not `3.4`. To get the fractional result, convert to `float64` first.

Integer division silently truncates

This is a common beginner mistake. 10 / 3 is 3, not 3.33. If you need the real division, convert at least one operand: float64(10) / float64(3) or 10.0 / 3.0.

Gocompound-assignment-operators.go

18 linesLn 1, Col 1Go

Compound assignment operators (`+=`, `-=`, `*=`, `/=`, `%=`) combine an operation with assignment. They are a shorthand only; there is no `++` or `--` as part of an expression in Go.

Comparison Operators

Comparison operators compare two values of the same type and always return a bool. You cannot use == between two values of different types without an explicit conversion.

Operator	Meaning	Example
==	Equal to	`5 == 5` → true
!=	Not equal to	`5 != 3` → true
<	Less than	`3 < 5` → true
<=	Less than or equal	`5 <= 5` → true
>	Greater than	`7 > 3` → true
>=	Greater than or equal	`3 >= 7` → false

Gousing-comparison-results.go

18 linesLn 1, Col 1Go

Comparison results are just `bool` values. You can store them in variables, pass them to functions, or use them directly in `if` conditions.

Logical Operators

Gological-operators-and-short-circuit-evaluation.go

28 linesLn 1, Col 1Go

Short-circuit evaluation is not just an optimization: it means the right side of `&&` only runs when the left side is `true`. This matters when the right side has a side effect or could panic.

String Operators

Go strings support + for concatenation and all six comparison operators. For building strings in a loop or from many parts, prefer strings.Builder or fmt.Sprintf over repeated +.

Gostring-operations.go

27 linesLn 1, Col 1Go

String `+` creates a new string each time. When building strings in a loop with many iterations, `strings.Builder` is dramatically faster because it amortizes allocations.

Operator Precedence

Goprecedence-and-parentheses.go

21 linesLn 1, Col 1Go

Add parentheses whenever the expression mixes `&&` and `||`. It prevents subtle logic bugs and makes the code immediately readable to other engineers.

When in doubt, parenthesize

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.