C++ 可以 setw 和 setfill 填充字符串的末尾吗？
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C++ can setw and setfill pad the end of a string?
提问by Dan
Is there a way to make setwand setfillpad the end of a string instead of the front?
有没有办法制作setw和setfill填充字符串的末尾而不是前面？
I have a situation where I'm printing something like this.
我有一种情况，我正在打印这样的东西。
CONSTANT TEXT variablesizeName1 .....:number1
CONSTANT TEXT varsizeName2 ..........:number2
I want to add a variable amount of '.'to the end of
我想'.'在末尾添加一个可变数量的
"CONSTANT TEXT variablesizeName#"so I can make ":number#"line up on the screen.
"CONSTANT TEXT variablesizeName#"所以我可以":number#"在屏幕上排队。
Note: I have an array of "variablesizeName#"so I know the widest case.
注意：我有一个数组，"variablesizeName#"所以我知道最广泛的情况。
Or
或者
Should I do it manually by setting setwlike this
我应该通过setw这样的设置手动进行吗
for( int x= 0; x < ARRAYSIZE; x++)
{
string temp = string("CONSTANT TEXT ")+variabletext[x];
cout << temp;
cout << setw(MAXWIDTH - temp.length) << setfill('.') <<":";
cout << Number<<"\n";
}
I guess this would do the job but it feels kind of clunky.
我想这可以完成这项工作，但感觉有点笨重。
Ideas?
想法？
回答by jrok
You can use manipulators std::left, std::right, and std::internalto choose where the fill characters go.
您可以使用操纵器std::left、std::right和std::internal来选择填充字符的位置。
For your specific case, something like this could do:
对于您的具体情况，可以这样做：
#include <iostream>
#include <iomanip>
#include <string>
const char* C_TEXT = "Constant text ";
const size_t MAXWIDTH = 10;
void print(const std::string& var_text, int num)
{
std::cout << C_TEXT
// align output to left, fill goes to right
<< std::left << std::setw(MAXWIDTH) << std::setfill('.')
<< var_text << ": " << num << '\n';
}
int main()
{
print("1234567890", 42);
print("12345", 101);
}
Output:
输出：
Constant text 1234567890: 42
Constant text 12345.....: 101
EDIT:
As mentioned in the link, std::internalworks only with integer, floating point and monetary output. For example with negative integers, it'll insert fill characters between negative sign and left-most digit.
编辑：如链接中所述，std::internal仅适用于整数、浮点数和货币输出。例如对于负整数，它会在负号和最左边的数字之间插入填充字符。
This:
这个：
int32_t i = -1;
std::cout << std::internal
<< std::setfill('0')
<< std::setw(11) // max 10 digits + negative sign
<< i << '\n';
i = -123;
std::cout << std::internal
<< std::setfill('0')
<< std::setw(11)
<< i;
will output
会输出
-0000000001
-0000000123
回答by Wug
Something like:
就像是：
cout << left << setw(MAXWIDTH) << setfill('.') << temp << ':' << Number << endl;
Produces something like:
产生类似的东西：
derp..........................:234
herpderpborp..................:12345678
回答by Chad
#include <iostream>
#include <iomanip>
int main()
{
std::cout
<< std::setiosflags(std::ios::left) // left align this section
<< std::setw(30) // within a max of 30 characters
<< std::setfill('.') // fill with .
<< "Hello World!"
<< "\n";
}
//Output:
Hello World!..................
