1、不需要参数的IO控制器的函数定义在<iosteram>中，其中包括dec,oct和hex.也包括ws,endl,ends和flush以及如下图所示的内容。
2、需要参数的控制器定义在<iomainip>头文件中，有如下的预定义的控制器
3、下边是使用IO控制器的例子程序
1: #include <fstream>
2: #include <iomanip>
3: using namespace std;
4:
5: int main() {
6: ofstream trc("trace.out");
7: int i = 47;
8: float f = 2300114.414159;
9: char* s = "Is there any more?";
10:
11: trc << setiosflags(
12: ios::unitbuf /*| ios::stdio */ /// ?????
13: | ios::showbase | ios::uppercase
14: | ios::showpos);
15: trc << i << endl; // Default to dec
16: trc << hex << i << endl;
17: trc << resetiosflags(ios::uppercase)
18: << oct << i << endl;
19: trc.setf(ios::left, ios::adjustfield);
20: trc << resetiosflags(ios::showbase)
21: << dec << setfill(‘0‘);
22: trc << "fill char: " << trc.fill() << endl;
23: trc << setw(10) << i << endl;
24: trc.setf(ios::right, ios::adjustfield);
25: trc << setw(10) << i << endl;
26: trc.setf(ios::internal, ios::adjustfield);
27: trc << setw(10) << i << endl;
28: trc << i << endl; // Without setw(10)
29:
30: trc << resetiosflags(ios::showpos)
31: << setiosflags(ios::showpoint)
32: << "prec = " << trc.precision() << endl;
33: trc.setf(ios::scientific, ios::floatfield);
34: trc << f << endl;
35: trc.setf(ios::fixed, ios::floatfield);
36: trc << f << endl;
37: trc.setf(0, ios::floatfield); // Automatic
38: trc << f << endl;
39: trc << setprecision(20);
40: trc << "prec = " << trc.precision() << endl;
41: trc << f << endl;
42: trc.setf(ios::scientific, ios::floatfield);
43: trc << f << endl;
44: trc.setf(ios::fixed, ios::floatfield);
45: trc << f << endl;
46: trc.setf(0, ios::floatfield); // Automatic
47: trc << f << endl;
48:
49: trc << setw(10) << s << endl;
50: trc << setw(40) << s << endl;
51: trc.setf(ios::left, ios::adjustfield);
52: trc << setw(40) << s << endl;
53:
54: trc << resetiosflags(
55: ios::showpoint | ios::unitbuf
56: // | ios::stdio // ?????????
57: );
58: } ///:~
.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }
4、输入如下
+47
0X2F
057
fill char: 0
+470000000
0000000+47
+000000047
+47
prec = 6
2.300115e+006
2300114.500000
2.30011e+006
prec = 20
2300114.5000000000000
2.30011450000000000000e+006
2300114.50000000000000000000
2300114.5000000000000
Is there any more?
0000000000000000000000Is there any more?
Is there any more?0000000000000000000000