signed Modifier

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Any integer type can be signedexplicitly declared as a signed type using the modifier.

Details

Integer types are encoded in modern systems as binary integers , with negative values ​​usually represented using two's complement . If a type specification such as char, short, int, longor long longthe modifier signedis specified, the integer type is explicitly declared as signed. This means that the type stores both negative and positive values. If the keyord is omitted, it is assumed by the compiler with the exception of the type by chardefault signed. It doesn't matter whether the keyword comes before, after, or in the middle of the type.

int               a;
signed int        b;
int signed        c;
char signed       d;
signed short      e;
long signed long  f;
signed            g;

If the base type is omitted from the declaration, the compiler automatically assumes the signed inttype .

The maximum and minimum possible values ​​of signedtypes are defined in the limitslibrary .

Arithmetic Conversion

In the case of assignments, initializations or casts to another integer type, the compiler may carry out arithmetic conversions . Due to the way negative numbers are encoded, it is fundamentally impossible to correctly convert a signed number to an unsigned type.

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printf("%u\n", (unsigned int) -123);

A Javascript program to illustrate the effects of cutting off bits can be found at Number System Converter ..