c输出格式

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
    //取整
    printf("%ld
",(long)19.999);
    //保留0位小数部分
    printf("%.lf
",19.999);

    //四舍五入
    //(long)是取整最右边的数据，而数据与数据之间以运算符号分开
    //所以一定要把数据和0.5用括号括起来，否则输出为0
    printf("%ld
",(long)(19.5+0.5));
    printf("%ld
",(long)(19.49+0.5));
    printf("%ld
",(long)(19.51+0.5));

    //整型用abs，实型用fabs
    printf("%ld
",abs(-5));
    printf("%lf
",fabs(-5.123));
    return 0;
}