学习C++笔记34

有符号与无符号整数例子（注意，测试平台为ubuntu 14.04 32位，gcc 4.8）

#include<iostream>

usingnamespace std;

int main()

{

 int n =0;

 n--;

 unsignedint u =(unsignedint)n;

 unsignedlonglongint v =(unsignedlonglongint)n;

 cout <<"Unsigned int value for "<< n <<" is "<< u <<"(0x"

      << hex << u <<")"<< endl;

 cout <<"0x"<< u <<" increase 1 is "<<(u+1)<< endl;

 cout <<"Unsigned long long int value for "<< dec << n <<" is "<< v <<"(0x"

      << hex << v <<")"<< endl;

 cout <<"0x"<< v <<" increase 1 is "<<(v+1)<< endl;

}

输出结果如下：

Unsignedint value for-1is4294967295(0xffffffff)

0xffffffff increase 1is0

Unsignedlonglongint value for-1is18446744073709551615(0xffffffffffffffff)

0xffffffffffffffff increase 1is0