如何将浮点数四舍五入到 C 中最接近的整数?
问题描述：
有没有办法在 C 中对数字进行四舍五入?
Is there any way to round numbers in C?
我不想使用 ceil 和 floor.还有其他选择吗?
I do not want to use ceil and floor. Is there any other alternative?
我在 Google 上搜索答案时遇到了这个代码片段:
I came across this code snippet when I Googled for the answer:
(int)(num < 0 ? (num - 0.5) : (num + 0.5))
即使 float num =4.9，上面的行也始终将值打印为 4.
The above line always prints the value as 4 even when float num =4.9.
答
4.9 + 0.5 是 5.4，除非你的编译器严重损坏，否则不可能四舍五入.
4.9 + 0.5 is 5.4, which cannot possibly round to 4 unless your compiler is seriously broken.
我刚刚确认 Google 搜索的代码给出了 4.9 的正确答案.
I just confirmed that the Googled code gives the correct answer for 4.9.
marcelo@macbookpro-1:~$ cat round.c
#include <stdio.h>
int main() {
float num = 4.9;
int n = (int)(num < 0 ? (num - 0.5) : (num + 0.5));
printf("%d\n", n);
}
marcelo@macbookpro-1:~$ make round && ./round
cc round.c -o round
5
marcelo@macbookpro-1:~$