如何求得int，unsigned，long int的最大值最小值？

[listevenly]

请教你们有什么好的方法？

[dragonzxh]

-2E(sizeof(int)) ---- 2E(sizeof(int))-1
其他一样吧

[dragonzxh]

写错
-2E(sizeof(int)*8) ---- 2E(sizeof(int)*8)-1

[ox_thedarkness]

使用头文件 limits

#include <limits>
#include <iostream>
using namespace std;

int main (){
cout<< numeric_limits<int>::max() << endl;
cout<< numeric_limits<unsigned>::max() <<endl;
cout<< numeric_limits<long int>::max() <<endl;

cout<<"-----------------------------"<<endl;

cout<< numeric_limits<int>::min() << endl;
cout<< numeric_limits<unsigned>::min() <<endl;
cout<< numeric_limits<long int>::min() <<endl;
}

[yuanchuang]

INT_MIN
INT_MAX
UINT_MAX
LONG_MIN
LONG_MAX
……

[jsjjms]

看看int，unsigned，long int在你的机器上都是多少位的，设为x
那么最大就是2^x-1

[firetoucher]

2 ox_thedarkness()
这是C语言，应该引用
#include <limits.h>
GNU limits.h的原文件：
-----------------------
/*
* limits.h
* This file has no copyright assigned and is placed in the Public Domain.
* This file is a part of the mingw-runtime package.
* No warranty is given; refer to the file DISCLAIMER within the package.
*
* Functions for manipulating paths and directories (included from io.h)
* plus functions for setting the current drive.
*
* Defines constants for the sizes of integral types.
*
* NOTE: GCC should supply a version of this header and it should be safe to
* use that version instead of this one (maybe safer).
*
*/

#ifndef _LIMITS_H_
#define _LIMITS_H_

/* All the headers include this file. */
#include <_mingw.h>

/*
* File system limits
*
* TODO: NAME_MAX and OPEN_MAX are file system limits or not? Are they the
* same as FILENAME_MAX and FOPEN_MAX from stdio.h?
* NOTE: Apparently the actual size of PATH_MAX is 260, but a space is
* required for the NUL. TODO: Test?
*/
#define PATH_MAX (259)

/*
* Characteristics of the char data type.
*
* TODO: Is MB_LEN_MAX correct?
*/
#define CHAR_BIT 8
#define MB_LEN_MAX 2

#define SCHAR_MIN (-128)
#define SCHAR_MAX 127

#define UCHAR_MAX 255

/* TODO: Is this safe? I think it might just be testing the preprocessor,
* not the compiler itself... */
#if ('\x80' < 0)
#define CHAR_MIN SCHAR_MIN
#define CHAR_MAX SCHAR_MAX
#else
#define CHAR_MIN 0
#define CHAR_MAX UCHAR_MAX
#endif

/*
* Maximum and minimum values for ints.
*/
#define INT_MAX 2147483647
#define INT_MIN (-INT_MAX-1)

#define UINT_MAX 0xffffffff

/*
* Maximum and minimum values for shorts.
*/
#define SHRT_MAX 32767
#define SHRT_MIN (-SHRT_MAX-1)

#define USHRT_MAX 0xffff

/*
* Maximum and minimum values for longs and unsigned longs.
*
* TODO: This is not correct for Alphas, which have 64 bit longs.
*/
#define LONG_MAX 2147483647L

#define LONG_MIN (-LONG_MAX-1)

#define ULONG_MAX 0xffffffffUL


/*
* The GNU C compiler also allows 'long long int'
*/
#if !defined(__STRICT_ANSI__) && defined(__GNUC__)

#define LONG_LONG_MAX 9223372036854775807LL
#define LONG_LONG_MIN (-LONG_LONG_MAX-1)

#define ULONG_LONG_MAX (2ULL * LONG_LONG_MAX + 1)

/* ISO C9x macro names */
#define LLONG_MAX LONG_LONG_MAX
#define LLONG_MIN LONG_LONG_MIN
#define ULLONG_MAX ULONG_LONG_MAX

/* MSVC compatibility */
#define _I64_MIN LONG_LONG_MIN
#define _I64_MAX LONG_LONG_MAX
#define _UI64_MAX ULONG_LONG_MAX

#endif /* Not Strict ANSI and GNU C compiler */


#endif /* not _LIMITS_H_ */

[ox_thedarkness]

orz... 貌似第二次在C区发了C++ ... = =b 下次就小心了....