Defined in header <iomanip> | ||
---|---|---|
/*unspecified*/ setbase( int base ); |
Sets the numeric base of the stream. When used in an expression out << setbase(base)
or in >> setbase(base)
, changes the basefield
flag of the stream out
or in
, depending on the value of base
:
16
sets basefield
to std::ios_base::hex
8
sets std::ios_base::oct
10
sets std::ios_base::dec
. Values of base
other than 8, 10, or 16 reset basefield
to zero, which corresponds to decimal output and prefix-dependent input.
base | - | new value for basefield |
Returns an object of unspecified type such that if str
is the name of an output stream of type std::basic_ostream<CharT, Traits>
or std::basic_istream<CharT, Traits>
, then the expression str << setbase(base)
or str >> setbase(base)
behaves as if the following code was executed:
str.setf(base == 8 ? std::ios_base::oct : base == 10 ? std::ios_base::dec : base == 16 ? std::ios_base::hex : std::ios_base::fmtflags(0), std::ios_base::basefield);
#include <iostream> #include <sstream> #include <iomanip> int main() { std::cout << "Parsing string \"10 0x10 010\"\n"; int n1, n2, n3; std::istringstream s("10 0x10 010"); s >> std::setbase(16) >> n1 >> n2 >> n3; std::cout << "hexadecimal parse: " << n1 << ' ' << n2 << ' ' << n3 << '\n'; s.clear(); s.seekg(0); s >> std::setbase(0) >> n1 >> n2 >> n3; std::cout << "prefix-dependent parse: " << n1 << ' ' << n2 << ' ' << n3 << '\n'; std::cout << "hex output: " << std::setbase(16) << std::showbase << n1 << ' ' << n2 << ' ' << n3 << '\n'; }
Output:
Parsing string "10 0x10 010" hexadecimal parse: 16 16 16 prefix-dependent parse: 10 16 8 hex output: 0xa 0x10 0x8
changes the base used for integer I/O (function) |
|
controls whether prefix is used to indicate numeric base (function) |
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