Princeton University COS 217: Introduction to Programming Systems C Primitive Data Types

Transcription

1 Princeton University COS 217: Introduction to Programming Systems C Primitive Data Types Type: int Size: System dependent. On FC010 with gcc217: 4 bytes. int ifirst; signed int isecond; decimal form negative form octal form 0x7B hexadecimal form largest smallest Type: unsigned int Size: System dependent. sizeof(unsigned int) == sizeof(int). On FC010 with gcc217: 4 bytes. unsigned int uifirst; unsigned uisecond; 123U decimal form 0173U octal form 0x7BU hexadecimal form U largest 0U smallest Type: long Size: System dependent. sizeof(long) >= sizeof(int). On FC010 with gcc217: 8 bytes. long lfirst; long int isecond; signed long lthird; signed long int lfourth; Page 1 of 5

2 Example Literals (assuming size is 8 bytes): Binary Representation/ 123L decimal form -123L negative form 0173L octal form 0x7BL hexadecimal form L largest L smallest Type: unsigned long Size: System dependent. sizeof(unsigned long) == sizeof(long). On FC010 with gcc217: 8 bytes. unsigned long ulfirst; unsigned long int ulsecond; Example Literals (assuming size is 8 bytes): Binary Representation/ 123UL decimal form 0173UL octal form 0x7BUL hexadecimal form UL largest 0UL smallest Type: char Usually represents a character according to a character code (e.g., ASCII). Size: 1 byte. char cfirst; signed char csecond; Example Literals (assuming the ASCII code is used): 'a' character form (char) decimal form (char) octal form (char)0x hexadecimal form '\o141' octal character form '\x61' hexadecimal character form Page 2 of 5

3 (char) decimal form (char) negative form (char) largest (char) smallest '\0' the null character '\a' bell '\b' backspace '\f' formfeed '\n' newline '\r' carriage return '\t' horizontal tab '\v' vertical tab '\\' backslash '\'' single quote Type: unsigned char Usually represents a character according to a character code (e.g., ASCII). Size: 1 byte. unsigned char ucfirst; Example Literals (assuming the ASCII code is used): (unsigned char)'a' character form (unsigned char) decimal form (unsigned char) largest (unsigned char) smallest : On most systems including FC010 with gcc217, "char" is the same as "signed char". On some systems, "char" is the same as "unsigned char". Type: short Size: System dependent. sizeof(short) <= sizeof(int). On FC010 with gcc217: 2 bytes. short sfirst; short int ssecond; signed short sthird; signed short int sfourth; Example Literals (assuming size is 2 bytes): (short) decimal form (short) negative form (short) largest (short) smallest (short) octal form (short)0x7b hexadecimal form Page 3 of 5

4 Type: unsigned short Size: System dependent. sizeof(unsigned short) == sizeof(short). On FC010 with gcc217: 2 bytes. unsigned short usfirst; unsigned short int ussecond; Example Literals (assuming size is 2 bytes): (unsigned short) decimal form (unsigned short) octal form (unsigned short)0x7b hexadecimal form (unsigned short) largest (unsigned short) smallest Type: double Description: A (positive or negative) double-precision floating point number. Size: System dependent. On FC010 with gcc217: 8 bytes. double dfirst; Example Literals (assuming size is 8 bytes): E2 scientific notation E E E E308 largest (approximate) E E-308 Type: float Description: A (positive or negative) single-precision floating point number. Size: System dependent. sizeof(float) <= sizeof(double). On FC010 with gcc217: 4 bytes. float ffirst; F Page 4 of 5

5 E2F scientific notation f E-2F F E2F F E-2F E38F E38F E-38F largest (approximate) Type: long double Description: A (positive or negative) extended-precision floating point number. Size: System dependent. sizeof(long double) >= sizeof(double). On FC010 with gcc217: 16 bytes. long double ldfirst; Example Literals (assuming size is 16 bytes): L E2L scientific notation l E-2L L E2L L E-2L E4932L E4932L E-4932L largest (approximate) Differences between C and Java: Java only: boolean, byte C only: unsigned char, unsigned short, unsigned int, unsigned long long double Java: Sizes of all types are specified C: Sizes of all types except char are system dependent Java: char comprises 2 bytes C: char comprises 1 byte Copyright 2015 by Robert M. Dondero, Jr. Page 5 of 5