iomanip

Xiangbuilder

这是怎回事？
谢谢。

1. 
   
2. #include <iostream>
   
3. #include <iomanip>
   
4. 
   
5. using namespace std;
   
6. 
   
7. int main () {
   
8.    for (int i=0; i<4; i++) {
   
9.       cout<<endl<<setfill(' ')<<setw(4-i)<<' 0'
   
10.           <<setfill(' *')<<setw(i+1)<<(i>0?' 0':' ');
    
11.    }
    
12. }
    

复制代码

[root@localhost exa]# g++ 33.cpp -o 33
33.cpp:8:44: warning: multi-character character constant
33.cpp:9:21: warning: multi-character character constant
33.cpp: In function `int main()':
33.cpp:9: error: no match for 'operator<<' in '
   (+std:perator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setw) [with
   _CharT = char, _Traits =
   std::char_traits<char>]((+std:perator<<(std::basic_ostream<_CharT,
   _Traits>&, std::_Setfill<_CharT>) [with _CharT = char, _Traits =
   std::char_traits<char>]((+(&std::cout)->std::basic_ostream<_CharT,
   _Traits>:perator<<(std::basic_ostream<_CharT,
   _Traits>&(*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char,
   _Traits = std::char_traits<char>](std::endl(std::basic_ostream<_CharT,
   _Traits>&) [with _CharT = char, _Traits = std::char_traits<char>])),
   std::setfill(_CharT) [with _CharT = char]())),
   std::setw(int)()))->std::basic_ostream<_CharT, _Traits>:perator<<(int)
   [with _CharT = char, _Traits = std::char_traits<char>](8240) <<
   std::setfill(_CharT) [with _CharT = int]()'
/usr/include/c++/3.3.2/bits/ostream.tcc:63: error: candidates are:
   std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT,
   _Traits>:perator<<(std::basic_ostream<_CharT,
   _Traits>&(*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char,

... ...
33.cpp:9:44: warning: multi-character character constant
[root@localhost exa]#

kj501

‘ ’表示一个单字节字符，你给它放进两个字符，能不出“warning: multi-character character constant”的警告吗？

kj501

看来你对字符和字符串的区别概念不清楚，好好看书。

Xiangbuilder

谢谢。