A signed integer represents both positive and negative values, while an unsigned integer represents only positive values. Range depends on the number of bits the compiler assigns for the representation.
bits max-negative max-positive max-unsigned
8 -128 +128 255
16 -32768 +32767 65535
32 -2147483648 +2147483647 4294967295
64 -9223372036854775808 +9223372036854775807 18446744073709551615
signed means both positive and negitive values .
unsigned means only positive values.
There are far more than 4 integral types in C++. As of C++11, there were 27 integral types: bool char signed char unsigned char wchar_t char16_t char32_t short signed short unsigned short short int signed short int unsigned short int int signed int unsigned int long signed long unsigned long long int signed long int unsigned long int long long signed long long unsigned long long long long int signed long long int unsigned long long int
The primitive data types in C include:[signed|unsigned] char[signed|unsigned] short[signed|unsigned] int[signed|unsigned] long[signed|unsigned] long longfloatdoublelong doubleEnumerations (enum) and arrays may also be considered to be primitive types.
Normally, signed and unsigned data types just refer to whether or not a value can be negative or not. An unsigned 4-bit value can be the values 0 to 15 A signed 4-bit value can be the values -8 to 7 However, there is no such thing as an unsigned value in Java*. All primitive types are signed by default and cannot change. *Note that technically a char value can be considered an unsigned type. The only way to see this is to declare a char with value '\uffff' (or 65535) and try to print it out as both a short and an int. If you try this with any other data types, the larger values will display the same as the smaller values. Not so with the char example.
One of them is signed, the other is unsigned.
Well, uh, const unsigned int and const signed int..
signed and unsigned
There are far more than 4 integral types in C++. As of C++11, there were 27 integral types: bool char signed char unsigned char wchar_t char16_t char32_t short signed short unsigned short short int signed short int unsigned short int int signed int unsigned int long signed long unsigned long long int signed long int unsigned long int long long signed long long unsigned long long long long int signed long long int unsigned long long int
Integer (signed or unsigned)
The primitive data types in C include:[signed|unsigned] char[signed|unsigned] short[signed|unsigned] int[signed|unsigned] long[signed|unsigned] long longfloatdoublelong doubleEnumerations (enum) and arrays may also be considered to be primitive types.
signed char unsigned long int void *
Normally, signed and unsigned data types just refer to whether or not a value can be negative or not. An unsigned 4-bit value can be the values 0 to 15 A signed 4-bit value can be the values -8 to 7 However, there is no such thing as an unsigned value in Java*. All primitive types are signed by default and cannot change. *Note that technically a char value can be considered an unsigned type. The only way to see this is to declare a char with value '\uffff' (or 65535) and try to print it out as both a short and an int. If you try this with any other data types, the larger values will display the same as the smaller values. Not so with the char example.
No, in Java, only signed numbers are defined.
One of them is signed, the other is unsigned.
I guess what you think of are these: short/long/long long, signed/unsigned
Well, uh, const unsigned int and const signed int..
There are four modifiers in C++: long, short, signed and unsigned. They are used to modify primitive types (int, char, float and double) to change their behaviour. If no type is specified, int is assumed. Thus a long long turns a 32-bit integer into a 64-bit integer while unsigned ensures an integer is always in the positive range.
In terms of storage there is no difference. A signed int is the same length (in bits) as an unsigned int. The only difference is the range of values that can be represented by those bits. With signed integers, the most-significant bit is used to denote the sign (0 = positive, 1 = negative), so an 8-bit signed char really only has 7-bits to store the value, thus limiting its positive range to [0:127] whereas the unsigned equivalent has the full 8-bits at its disposal so can represent values in the range [0:255]. Another difference is the way in which negative values are physically represented. There are in fact two ways of achieving this depending on the hardware. Older hardware generally uses ones-complement notation, which simply switches every bit. Thus 00101010 (+42) becomes 11010101 (-42). However, since the value zero is neither positive nor negative, we end up with two representations for the value zero (00000000 and 11111111). This also limits the range to [-127:127] for 8-bit signed values. Newer hardware uses twos-complement notation. To switch the sign, we first take the ones-complement as before but we then add 1 and ignore any overflow. Thus 00000000 becomes 11111111 + 1 which is 00000000. This, in turn, increases the negative range by 1, such that an 8-bit signed char now has a range of [-128:127]. Generally speaking, we use unsigned integers whenever we need to represent natural numbers, such as file sizes or array sizes; values that can never be negative. For all other work, we use signed integers. Note that in C++ a plain char may be signed or unsigned (depending on the implementation), but is not considered the same type as either a signed or unsigned char. They are three completely independent types. Thus a plain char is only guaranteed to represent values in the range [0:127], the ASCII character codes; the only values common to both signed and unsigned char. If you specifically need to represent values outwith this range, such as [-128:127] or [0:255], use an explicitly signed or unsigned char respectively. All other integer types (short, int, long and long long) are implicitly signed unless you explicitly declare them with the unsigned modifier. Note also that floats, doubles and long doubles are always signed (they cannot be modified).