C++/Data Type/double output — различия между версиями
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Admin (обсуждение | вклад) м (1 версия: Импорт контента...) |
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Текущая версия на 13:27, 25 мая 2010
Содержание
- 1 double: Formatting aligns columns, pads blank spaces with "0" character, and controls precision of answer.
- 2 Fixed format with precision of 7
- 3 Scientific format with precision of 7
- 4 Set fixed flag for double value
- 5 Set scientific flag when outputing double
- 6 Set showpos flag for double
- 7 Set the precision to 9
- 8 Set the uppercase flag for double value
double: Formatting aligns columns, pads blank spaces with "0" character, and controls precision of answer.
<source lang="cpp">
- include <iostream>
- include <iomanip>
- include <math.h>
using namespace std; main( ) {
double number,square,sqroot; cout << "num\t" << "square\t\t" << "square root\n"; number=1.0; cout.setf(ios::fixed); for(int i=1;i<16;i++) { square=number*number; sqroot=sqrt(number); cout.fill("0"); // fill blanks with zeros cout.width(2); // column 2 characters wide cout.precision(0); // no decimal place cout << number << "\t"; cout.width(6); // column 6 characters wide cout.precision(1); // print 1 decimal place cout << square << "\t\t"; cout.width(8); // column 8 characters wide cout.precision(6); // print 6 decimal places cout << sqroot << endl; number+=1.0; } return (0);
}
</source>
Fixed format with precision of 7
<source lang="cpp">
- include <iostream>
- include <iomanip>
using namespace std; int main() {
cout << "Default format: " << 123.123456789 << endl; cout << "Fixed format with precision of 7: "; cout << setprecision(7) << fixed << 123.123456789 << endl; return 0;
}
</source>
Scientific format with precision of 7
<source lang="cpp">
- include <iostream>
- include <iomanip>
using namespace std; int main() {
cout << "Default format: " << 123.123456789 << endl; cout << "Scientific format with precision of 7: "; cout << scientific << 123.123456789 << endl; return 0;
}
</source>
Set fixed flag for double value
<source lang="cpp">
- include <iostream>
using namespace std; int main() {
int x = 100; double f = 98.6; double f2 = 123456.0; double f3 = 1234567.0; cout.setf(ios::fixed, ios::floatfield); cout << "After setting fixed flag:\n"; cout << "f: " << f << " f2: " << f2 << " f3: " << f3 << "\n\n"; return 0;
}
</source>
Set scientific flag when outputing double
<source lang="cpp">
- include <iostream>
using namespace std; int main() {
int x = 100; double f = 98.6; double f2 = 123456.0; double f3 = 1234567.0; cout.setf(ios::scientific, ios::floatfield); cout << "After setting scientific flag:\n"; cout << "f: " << f << " f2: " << f2 << " f3: " << f3 << endl;
return 0;
}
</source>
Set showpos flag for double
<source lang="cpp">
- include <iostream>
using namespace std; int main() {
int x = 100; double f = 98.6; double f2 = 123456.0; double f3 = 1234567.0; // Set the showpos flag. cout.setf(ios::showpos); cout << "Setting showpos flag.\n"; cout << "f in default notation after setting showpos: " << f << "\n\n"; return 0;
}
</source>
Set the precision to 9
<source lang="cpp">
- include <iostream>
using namespace std; int main() {
double f = 123456.123456789; cout << "Using default numeric format.\n"; cout << "f with default precision: " << f << "\n\n"; cout << "Setting the precision to 9.\n"; cout.precision(9); cout << "f with precision of 9: " << f << "\n\n"; cout << "Switching to fixed-point format.\n"; cout.setf(ios::fixed, ios::floatfield); cout << "f with precision of 9 in fixed-point: " << f << "\n\n"; // Now, display two decimal places. cout << "Display two decimal places in all cases: "; cout.precision(2); cout << 12.456 << " " << 10.0 << " " << 19.1 << endl; return 0;
}
</source>
Set the uppercase flag for double value
<source lang="cpp">
- include <iostream>
using namespace std; int main() {
int x = 100; double f = 98.6; double f2 = 123456.0; double f3 = 1234567.0; // Set the uppercase flag. cout << "Setting uppercase flag.\n"; cout.setf(ios::uppercase); cout << "f3 with uppercase flag set: " << f3 << endl; return 0;
}
</source>