C语言 如何限制 printf 在小数点后显示的位数？
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How can I limit the number of digits displayed by printf after the decimal point?
提问by Sarah Dawkins
I wrote a small program that reads two integers using scanfand then performs various arithmetic calculations. I'm using printfto display the results. How can I make printfdisplay only two digits after the decimal point? Starting with the simplified code sample:
我写了一个小程序，它使用读取两个整数scanf，然后执行各种算术计算。我printf用来显示结果。如何让printf小数点后只显示两位数？从简化的代码示例开始：
#include <stdio.h>
int main(void)
{
double third = 1.0 / 3.0;
// display data
printf("\n%20s%20s", "Description", "Data");
printf("\n%20s%20s", "-----------", "----");
printf("\n%20s%20lf", "One third", third);
printf("\n");
return 0;
}
This prints "0.333333" for the value of third. How would I alter the above to get the following output?
这将为 的值打印“0.333333” third。我将如何更改上述内容以获得以下输出？
Description Data
----------- ----
One third 0.33
Description Data
----------- ----
One third 0.33
回答by Derrick Zhang
use "%.2f" at the place you want.
在你想要的地方使用“%.2f”。
For example, modify the following statement
比如修改下面的语句
printf("\n%20s%20lf", "Fraction", quotientdecimal);
into this one :
进入这个：
printf("\n%20s%.2f", "Fraction", quotientdecimal);
will only display two fraction numbers of the variable quotlentdecimal.
将只显示变量 quotlentdecimal 的两个小数。
