Data Type Identifier - Problem

Given a value, determine whether it is an integer, float, string, or boolean.

Your task is to analyze the input value and return the appropriate data type as a string. The function should be able to distinguish between:

"integer" - whole numbers like 42, -15, 0
"float" - decimal numbers like 3.14, -2.5, 0.0
"string" - text values like "hello", "123abc", ""
"boolean" - true or false values

Return the detected type as a lowercase string.

Input & Output

Example 1 — Integer Value

$ Input: value = "42"

› Output: "integer"

💡 Note: The string "42" represents a whole number without decimal places, so it's classified as an integer.

Example 2 — Float Value

$ Input: value = "3.14"

› Output: "float"

💡 Note: The string "3.14" contains a decimal point and represents a floating-point number.

Example 3 — Boolean Value

$ Input: value = "true"

› Output: "boolean"

💡 Note: The string "true" is a boolean value (case-insensitive match).

Constraints

Input will be a string representation of a value
Boolean values are case-insensitive ("True", "FALSE", etc.)
Integer values can be positive or negative
Float values must contain a decimal point

Visualization

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Asked in

M Microsoft 25 🍎 Apple 18

The key insight is to use built-in type conversion functions to test if a string can be parsed as different data types. The optimal approach uses language-specific parsing functions with proper error handling. Time: O(1), Space: O(1)

Common Approaches

✓ Built-in Type Checking

⏱️ Time: O(1) Space: O(1)

Leverage the programming language's built-in type checking capabilities to directly determine the type of the input value. This is more reliable and efficient than manual pattern matching.

Manual String Analysis

⏱️ Time: O(n) Space: O(1)

Convert the input to string and manually analyze its format by checking for numeric patterns, decimal points, and boolean keywords. This involves multiple conditional checks to determine the type.

Built-in Type Checking — Algorithm Steps

Use built-in type checking functions
Check against each target type in order
Return the matching type name as string

Visualization

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Step-by-Step Walkthrough

Input Processing

Receive input value as string

Built-in Check

Use language functions to test type conversion

Instant Result

Return detected type immediately

Code -

solution.c — C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

char* solution(char* value) {
    static char result[20];
    
    // Check boolean first
    if (strcasecmp(value, "true") == 0 || strcasecmp(value, "false") == 0) {
        strcpy(result, "boolean");
        return result;
    }
    
    // Check if contains decimal point
    if (strchr(value, '.') != NULL) {
        char* endptr;
        double d = strtod(value, &endptr);
        if (*endptr == '\0' && endptr != value) {
            strcpy(result, "float");
            return result;
        }
    } else {
        char* endptr;
        long l = strtol(value, &endptr, 10);
        if (*endptr == '\0' && endptr != value) {
            strcpy(result, "integer");
            return result;
        }
    }
    
    strcpy(result, "string");
    return result;
}

int main() {
    char value[1000];
    fgets(value, sizeof(value), stdin);
    value[strcspn(value, "\n")] = 0;
    
    char* result = solution(value);
    printf("%s\n", result);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(1)

Built-in type checking functions execute in constant time

✓ Linear Growth

Space Complexity

O(1)

Only use a few variables, no additional data structures needed

✓ Linear Space

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Data Type Identifier - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Built-in Type Checking — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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