Built-in Functions Overview

Common Pseudocode provides a rich set of built-in functions to perform common operations. These functions are organized into several categories:

Function Categories

Math Functions

Functions for mathematical operations including rounding, absolute values, square roots, and random number generation.

See the Math Functions page for details.

String Functions

Functions for manipulating and analyzing text strings, including case conversion, substring operations, and splitting.

See the String Functions page for details.

Array Functions

Functions for working with arrays, including adding, removing, and searching for elements.

See the Array Functions page for details.

Type Checking

Functions to check the type of a value at runtime.

See the Type Checking page for details.

Function Calling Syntax

Common Pseudocode supports multiple syntax styles for calling functions:

Standard Syntax

result = functionName(arg1, arg2)

Natural Language Syntax

result = run functionName with arg1 and arg2

Operator-style Syntax

For some functions, you can use natural language operators:

squareRoot = sqrt of 16
absolute = abs of -5
textLength = length of "hello"

Function Composition

You can combine functions to perform complex operations:

// Nested function calls
result = round(sqrt of 16)      // 4

// Using results in expressions
text = "  hello  "
trimmed = trim(text to uppercase)  // "HELLO"

// Chaining with variables
numbers = [3.7, 2.1, 8.9, 4.2]
sum = 0
for each num in numbers
    sum = sum + round(num)
output "Sum of rounded numbers: {sum}"  // 19

Common Patterns

Input Validation

output "Enter your age: "
input ageInput

if is number(convert ageInput to number)
    age = convert ageInput to number
    if age >= 0 AND age <= 120
        output "Valid age: {age}"
    else
        output "Age out of range"
else
    output "Not a valid number"

Array Processing

scores = [85, 92, 78, 95, 88]

// Calculate average
sum = 0
for each score in scores
    sum = sum + score
average = sum / length of scores
output "Average: {average}"

// Find highest score
highest = scores[0]
for each score in scores
    highest = max(highest, score)
output "Highest score: {highest}"

String Formatting

firstName = "john"
lastName = "doe"

// Convert to title case
firstName = substring of (firstName to uppercase) from 0 to 1
    concat substring of firstName from 1 to length of firstName

lastName = substring of (lastName to uppercase) from 0 to 1
    concat substring of lastName from 1 to length of lastName

fullName = join [firstName, lastName] with " "
output fullName  // "John Doe"

Random Selection

options = ["Rock", "Paper", "Scissors"]
randomIndex = random integer from 0 to length of options - 1
choice = options[randomIndex]
output "Computer chose: {choice}"

Combining Built-in and User-Defined Functions

Built-in functions work seamlessly with your custom functions:

function calculateCircleArea takes in radius
    constant PI = 3.14159
    return PI * (radius ^ 2)

function formatArea takes in area
    rounded = round(area)
    return "Area: " convert rounded to string " sq units"

// Using both together
radius = 5.7
area = calculateCircleArea(radius)
output formatArea(area)  // "Area: 102 sq units"

Function Return Values

Most built-in functions return values that can be:

Stored in Variables

result = sqrt of 16
output result

Used Directly in Expressions

if length of name > 0
    output "Valid name"

Passed to Other Functions

rounded = round(sqrt of 20)  // round(4.472...) = 4

Used in Conditions

if is number(userInput)
    // Process numeric input

Error Handling with Functions

Some functions may fail or return special values:

try
    // Division might fail
    result = 10 / denominator
    output round(result)
catch error
    output "Cannot calculate result"

// Checking for null returns
index = find "xyz" in text
if index equals -1
    output "Not found"
else
    output "Found at position {index}"

Best Practices

1. Use Descriptive Variable Names

// Good
userAge = convert ageInput to number
validEmail = email contains "@"

// Avoid
x = convert y to number
flag = email contains "@"

2. Combine Related Operations

// Instead of multiple conversions
cleanedInput = trim(userInput to lowercase)

// Break into steps for complex operations
rawInput = userInput
trimmed = trim(rawInput)
cleaned = trimmed to lowercase

3. Check Types Before Operations

if is array(data) AND length of data > 0
    firstElement = data[0]
    output firstElement

4. Handle Edge Cases

function safeDivide takes in numerator and denominator
    if denominator equals 0
        return 0
    return round(numerator / denominator)

User-Defined Functions

You can create your own functions using the function keyword:

function add takes in num1 and num2
    return num1 + num2

result = add(5, 3)  // 8
result = run add with 5 and 3  // 8

See the Creating Functions page for a comprehensive guide on creating your own functions, including examples, best practices, and advanced techniques.