本文整理汇总了C++中std::basic_ostream::precision方法的典型用法代码示例。如果您正苦于以下问题：C++ basic_ostream::precision方法的具体用法？C++ basic_ostream::precision怎么用？C++ basic_ostream::precision使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类std::basic_ostream的用法示例。
在下文中一共展示了basic_ostream::precision方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: fprint
inline void fprint(std::basic_ostream<Elem, Traits>& out, const std::basic_string<Elem, Traits>& str, Args&&... arguments) {
if(sizeof...(arguments) < 1) {
out << str;
return;
}
auto args = std::make_tuple(std::forward<Args>(arguments)...);
string::is_digit cmp;
auto&& length = str.size();
auto&& original_width = out.width();
std::ios_base::fmtflags original_format = out.flags();
auto&& original_precision = out.precision();
for(decltype(str.size()) i = 0; i < length; ++i) {
auto&& c = str[i];
// doesn't start with { so just print it and continue
if(c != out.widen('{')) {
out << c;
continue;
}
// at this point, the character c points to {
// check if we're done printing
if(i + 1 > length) {
out << c;
break;
}
// check the next characters
auto j = i + 1;
unsigned index = 0;
decltype(out.width()) width = 0;
decltype(out.precision()) precision = 0;
auto format = original_format;
// escaped character
if(str[j] == out.widen('{')) {
out << str[i];
i = j;
continue;
}
// now we're at a sane point where we can work with the format string
// check if the next character is a digit
if(cmp(str[j])) {
do {
// since it is, multiply the index
index = (index * 10) + (str[j++] - out.widen('0'));
}
while(j < length && cmp(str[j]));
}
else {
// since it isn't a digit, it doesn't match our format string
throw std::runtime_error("invalid format string specified");
}
// check if alignment argument exists
if(str[j] == out.widen(',')) {
// check if the next character is valid
if(j + 1 < length) {
// check if the alignment is left or right
if(str[j + 1] == out.widen('-')) {
format |= out.left;
// increment by two to get to the numerical section
j += 2;
}
else {
format |= out.right;
++j;
}
// check if the next character is a digit
if(j < length && cmp(str[j])) {
do {
// since it is, multiply the width
width = (width * 10) + (str[j++] - out.widen('0'));
}
while(j < length && cmp(str[j]));
}
else {
// invalid format string found
throw std::runtime_error("invalid format string specified");
}
}
}
// check if format specifier exists
if(str[j] == out.widen(':')) {
// check if the character is valid
if(j + 1 < length) {
auto&& specifier = str[j + 1];
switch(specifier) {
case 'F':
format |= out.fixed;
break;
case 'O':
format = (format & ~out.basefield) | out.oct;
break;
case 'x':
//.........这里部分代码省略.........