Difference between revisions of "C datatypes"

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=Int and long int=
 
=Int and long int=
 +
See the file limits.h for details - Properly at /usr/include/limits.h
 
<source lang=c>
 
<source lang=c>
 
#include <stdio.h>
 
#include <stdio.h>
−
//Author: heth@mercantec.dk
+
#include <limits.h>
  
−
int main( void ) {
+
int main() {
−
        int int_max,int_min;
+
  printf("Wordsize is %d\n\n", __WORDSIZE);
−
        unsigned int uint_max;
+
  printf("The number of bits in a byte %d\n", CHAR_BIT);
−
        long int lint_max,lint_min;
 
−
        unsigned long int ulint_max;
 
  
−
        printf("Integer size = %i - long integer size = %i\n",
+
  printf("The minimum value of SIGNED CHAR = %d\n", SCHAR_MIN);
−
                (int) sizeof(int_max), (int) sizeof(lint_max) );
+
  printf("The maximum value of SIGNED CHAR = %d\n", SCHAR_MAX);
−
        printf("================= integer ================\n");
+
  printf("The maximum value of UNSIGNED CHAR = %d\n", UCHAR_MAX);
−
        int_max = 0x7fffffff;
 
−
        int_min = 0x80000000;
 
−
        printf("int_max = %i og int_min = %i\n", int_max,int_min);
 
−
        int_max++;
 
−
        int_min--;
 
−
        printf("int_max = %i og int_min = %i\n", int_max,int_min);
 
−
        printf("=========== Unsigned integer =============\n");
 
−
        uint_max = 0xffffffff;
 
−
        printf("uint_max = %u\n" , uint_max);
 
−
        uint_max++;
 
−
        printf("uint_max = %u\n", uint_max);
 
  
−
        printf("==============Long integer ===============\n");
+
  printf("The minimum value of SHORT INT = %d\n", SHRT_MIN);
−
        lint_max = 0x7fffffffffffffff;
+
  printf("The maximum value of SHORT INT = %d\n", SHRT_MAX);  
−
        lint_min = 0x8000000000000000;
+
 
−
        printf("lint_max = %li og lint_min = %li\n", lint_max,lint_min);
+
  printf("The minimum value of INT = %d\n", INT_MIN);
−
        lint_max++;
+
  printf("The maximum value of INT = %d\n", INT_MAX);
−
        lint_min--;
+
 
−
        printf("lint_max = %li og lint_min = %li\n", lint_max,lint_min);
+
  printf("The minimum value of CHAR = %d\n", CHAR_MIN);
−
        printf("=========== Unsigned integer =============\n");
+
  printf("The maximum value of CHAR = %d\n", CHAR_MAX);
−
        ulint_max = 0xffffffffffffffff;
+
 
−
        printf("ulint_max = %lu\n" , ulint_max);
+
  printf("The minimum value of LONG = %ld\n", LONG_MIN);
−
        ulint_max++;
+
  printf("The maximum value of LONG = %ld\n", LONG_MAX);
−
        printf("ulint_max = %lu\n", ulint_max);
+
 
 +
  return(0);
 
}
 
}
−
 
 
</source>
 
</source>
 
==Compiling and running==
 
==Compiling and running==
 +
===On a 64 bit system===
 
<source lang=bash>
 
<source lang=bash>
−
heth@mars:~/bin$ gcc -v
 
−
gcc version 4.4.5 (Ubuntu/Linaro 4.4.5-15ubuntu1)
 
−
heth@mars:~/bin$ uname -a
 
−
Linux mars 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 02:41:37 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux
 
 
heth@mars:~/bin$ gcc types.c -o types
 
heth@mars:~/bin$ gcc types.c -o types
 
heth@mars:~/bin$ ./types
 
heth@mars:~/bin$ ./types
−
Integer size = 4 - long integer size = 8
+
Wordsize us 64
−
================= integer ================
+
 
−
int_max = 2147483647 og int_min = -2147483648
+
The number of bits in a byte 8
−
int_max = -2147483648 og int_min = 2147483647
+
The minimum value of SIGNED CHAR = -128
−
=========== Unsigned integer =============
+
The maximum value of SIGNED CHAR = 127
−
uint_max = 4294967295
+
The maximum value of UNSIGNED CHAR = 255
−
uint_max = 0
+
The minimum value of SHORT INT = -32768
−
==============Long integer ===============
+
The maximum value of SHORT INT = 32767
−
lint_max = 9223372036854775807 og lint_min = -9223372036854775808
+
The minimum value of INT = -2147483648
−
lint_max = -9223372036854775808 og lint_min = 9223372036854775807
+
The maximum value of INT = 2147483647
−
=========== Unsigned integer =============
+
The minimum value of CHAR = -128
−
ulint_max = 18446744073709551615
+
The maximum value of CHAR = 127
−
ulint_max = 0
+
The minimum value of LONG = -9223372036854775808
−
heth@mars:~/bin$
+
The maximum value of LONG = 9223372036854775807
 
</source>
 
</source>
  
 +
===On a 32 bit system===
 +
<source lang=bash>
 +
heth@mars:~/bin$ gcc types.c -o types
 +
heth@mars:~/bin$ ./types
 +
Wordsize is 32
 +
 +
The number of bits in a byte 8
 +
The minimum value of SIGNED CHAR = -128
 +
The maximum value of SIGNED CHAR = 127
 +
The maximum value of UNSIGNED CHAR = 255
 +
The minimum value of SHORT INT = -32768
 +
The maximum value of SHORT INT = 32767
 +
The minimum value of INT = -2147483648
 +
The maximum value of INT = 2147483647
 +
The minimum value of CHAR = 0
 +
The maximum value of CHAR = 255
 +
The minimum value of LONG = -2147483648
 +
The maximum value of LONG = 2147483647
 +
The minimum value of LONG = -2147483648
 +
The maximum value of UNSIGNED LONG = 2147483647
 +
</source>
 
[[Category:C]]
 
[[Category:C]]

Latest revision as of 10:17, 27 November 2022

Int and long int

See the file limits.h for details - Properly at /usr/include/limits.h 

#include <stdio.h>
#include <limits.h>

int main() {
   printf("Wordsize is %d\n\n", __WORDSIZE);
   printf("The number of bits in a byte %d\n", CHAR_BIT);

   printf("The minimum value of SIGNED CHAR = %d\n", SCHAR_MIN);
   printf("The maximum value of SIGNED CHAR = %d\n", SCHAR_MAX);
   printf("The maximum value of UNSIGNED CHAR = %d\n", UCHAR_MAX);

   printf("The minimum value of SHORT INT = %d\n", SHRT_MIN);
   printf("The maximum value of SHORT INT = %d\n", SHRT_MAX); 

   printf("The minimum value of INT = %d\n", INT_MIN);
   printf("The maximum value of INT = %d\n", INT_MAX);

   printf("The minimum value of CHAR = %d\n", CHAR_MIN);
   printf("The maximum value of CHAR = %d\n", CHAR_MAX);

   printf("The minimum value of LONG = %ld\n", LONG_MIN);
   printf("The maximum value of LONG = %ld\n", LONG_MAX);
  
   return(0);
}

Compiling and running

On a 64 bit system

heth@mars:~/bin$ gcc types.c -o types
heth@mars:~/bin$ ./types
Wordsize us 64

The number of bits in a byte 8
The minimum value of SIGNED CHAR = -128
The maximum value of SIGNED CHAR = 127
The maximum value of UNSIGNED CHAR = 255
The minimum value of SHORT INT = -32768
The maximum value of SHORT INT = 32767
The minimum value of INT = -2147483648
The maximum value of INT = 2147483647
The minimum value of CHAR = -128
The maximum value of CHAR = 127
The minimum value of LONG = -9223372036854775808
The maximum value of LONG = 9223372036854775807

On a 32 bit system

heth@mars:~/bin$ gcc types.c -o types
heth@mars:~/bin$ ./types
Wordsize is 32

The number of bits in a byte 8
The minimum value of SIGNED CHAR = -128
The maximum value of SIGNED CHAR = 127
The maximum value of UNSIGNED CHAR = 255
The minimum value of SHORT INT = -32768
The maximum value of SHORT INT = 32767
The minimum value of INT = -2147483648
The maximum value of INT = 2147483647
The minimum value of CHAR = 0
The maximum value of CHAR = 255
The minimum value of LONG = -2147483648
The maximum value of LONG = 2147483647
The minimum value of LONG = -2147483648
The maximum value of UNSIGNED LONG = 2147483647
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