C++

参考

<ios>

ios

public member function
<ios> <iostream>

std::ios::fill

get (1)
char fill() const;
set (2)
char fill (char fillch);
Get/set fill character
The first form (1) returns the fill character.

The second form (2) sets fillch as the new fill character and returns the fill character used before the call.

The fill character is the character used by output insertion functions to fill spaces when padding results to the field width.

The parametric manipulator setfill can also be used to set the fill character.

参数

fillch
the new fill character.

返回值

The value of the fill character before the call.

示例

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// using the fill character
#include <iostream>     // std::cout

int main () {
  char prev;

  std::cout.width (10);
  std::cout << 40 << '\n';

  prev = std::cout.fill ('x');
  std::cout.width (10);
  std::cout << 40 << '\n';

  std::cout.fill(prev);

  return 0;
}

输出
        40
xxxxxxxx40


数据竞争

Accesses (1) or modifies (2) the stream object.
并发访问同一个流对象可能导致数据争用。

异常安全

基本保证：如果抛出异常，流处于有效状态。

另见

setfill
设置填充字符 (函数)
ios_base::width
获取/设置字段宽度 （公开成员函数）