C++ Fundamentals 007 [Notes Version – Data Type Conversion]

Click the blueFollow usC++ Fundamentals 007 – Data Type ConversionIntegerFloating PointCharacter01Automatic Conversion [Implicit Conversion]

Small box → big box, can fit automatically

It’s like pouring the contents of a small box into a big box without manual operation; the computer will complete it automatically.Characteristics: Safe, no data loss.1>>>Integer (int) to Decimal (double)

<span>int</span> is a small box for integers (e.g., <span>5</span>), <span>double</span> is a big box for decimals (e.g., <span>5.0</span>). When putting an integer into a decimal box, the computer will automatically add <span>.0</span> at the end.

2>>>Character (char) to Integer (int)

<span>char</span> holds a single character (e.g., <span>'A'</span>), but the computer actually stores characters as numbers (ASCII code). When putting a character into an integer box, it will automatically convert to the corresponding number.

02Forced Conversion: Big Box → Small Box, requires manual “squeezing”

It’s like stuffing the contents of a big box into a small box; you must manually tell the computer “I want to do this,” and it may “squeeze out” some content (data loss).

※ Format: (target type) data to convert

1>>>Decimal (double) to Integer (int)

The content in the decimal box (e.g., <span>3.8</span>) is larger than the integer box, and during forced conversion, the decimal part will be “cut off,” leaving only the integer.

2>>>Integer (int) to Character (char)

If the number in the integer box is between 0-127 (ASCII code range), it can be forcibly converted to the corresponding character; exceeding this range may yield strange symbols.

03Summary: When to use which conversion?

🔁 Remember the following two aspects:

1.Automatic Conversion:

• Small box → big box (e.g., <span>int</span> → <span>double</span>, <span>char</span> → <span>int</span>): The computer converts automatically, use with confidence.

2.Manual Conversion:

• Big box → small box (e.g., <span>double</span> → <span>int</span>, <span>int</span> → <span>char</span>): Must use <span>(target type)</span> for manual conversion, and be aware of potential data loss (e.g., converting decimal to integer will lose the decimal part).

Summary:It’s easy to put small building blocks into a big box (automatic conversion); stuffing a big toy into a small box requires effort and may damage a bit (forced conversion)~

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C++ Fundamentals 001 [Notes Version]C++ Fundamentals 002 [Notes Version]C++ Fundamentals 003 [Notes Version – Operator Summary]C++ Fundamentals 004 [Notes Version – Common Data Types]C++ Fundamentals 005 [Notes] Common Mathematical Library FunctionsC++ Fundamentals 006 [Notes Version – Three Major Structures]