What is the difference between char and unsigned char

char and unsigned char are two data types that store character data. The main difference is the way of dealing with negative and positive numbers: value range: char signed (-128 to 127), and unsigned char unsigned (0 to 255). Negative number processing: char can store negative numbers, unsigned char cannot. Bit mode: char The highest bit represents the symbol, unsigned char Unsigned bit. Arithmetic operations: char and unsigned char are signed and unsigned types, and their arithmetic operations are different. Compatibility: char and unsigned char

The difference between char and unsigned char

char and unsigned char are two data types used in C language to store character type data. The main difference between them is the way they deal with negative and positive numbers respectively.

1. Value range

• char: signed integer with values ​​ranging from -128 to 127.
• unsigned char: Unsigned integer with values ​​ranging from 0 to 255.

2. Negative number processing

• char: It can store negative numbers, and when storing negative numbers, it uses complement notation.
• unsigned char: Cannot store negative numbers, attempting to store negative numbers will produce an unsigned value.

3. Bit mode

• char: The highest bit (sign bit) when stored means positive and negative, 0 means positive and 1 means negative.
• unsigned char: There are no sign bits, all bits are used to represent non-negative numbers.

4. Arithmetic operations

• Arithmetic operations deal with char and unsigned char differently because char is signed, while unsigned char is unsigned.

5. Compatibility

• char and unsigned char are incompatible with each other, which means that the char value cannot be assigned directly to the unsigned char variable and vice versa.

Example:

 <code class="c">char c = -1; // 有符号值-1 unsigned char uc = c; // 转换为无符号值255</code>

in conclusion:

char and unsigned char are different data types used to store character type data. Their main differences are in how they handle negative and positive numbers, value ranges, and behavior in arithmetic operations.

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