#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 100

int main()
{

    float  ten_hex = 0;
    int     inum = 0;
    float  fnum = 0;

    scanf ("%f", &ten_hex);

    inum = (int)ten_hex;
    fnum = ten_hex - inum;

    printf ("inum is %d\nfnum = %f\n", inum, fnum);    //输入123.456          结果   inum = 123, fnum = 0.456001        后面的1哪来的。。。

    return 0;
}

精度问题

该怎么改呢，我想保留小数点后6位。不要随机数

用double好一点

double也有随机数

 ./a.exe
123.456
inum is 123
fnum = 0.456000

    double  ten_hex = 0;
    int     inum = 0;
    double  fnum = 0;

    scanf ("%lf", &ten_hex);

其实我一直没搞明白double输入的时候是%lf还是%f 好在输入浮点数的时候不多

其实原因是你这里实现方法不好 我感觉应该是这样

函数名: modf   功 能: 把数分为整数和小数 （The modf function breaks down the floating-point value x into fractional and integer parts, each of which has the same sign as x. The signed fractional portion of x is returned. The integer portion is stored as a floating-point value at intptr.   ）   
用 法: double modf(double x, double *intptr);   程序例:   #include <math.h>   #include <stdio.h>   int main(void)   {   double fraction, integer;   double number = 100000.567;   fraction = modf(number, &integer);   printf("The whole and fractional parts of %lf are %lf and %lf\n",   number, integer, fraction);   return 0;   }

啊 百度百科复制过来就乱了 慢慢看罢

http://baike.baidu.com/view/1682851.htm

我觉得应该用这个函数 就是上面贴的那些

嘿嘿

。。路过。。。

先谢谢z版,问题虽然解决了，但是我的疑问还是没有解决。。。为什么后面会出现随机数呢？