已知float后几位,谋几位保留

设变量n为float类型,m为int类型,则以下能实现将n中的数值保留小数点后两位,第三位进行四舍五入运算的表达式____.

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

//#define
static float Mathematical_modeling = ;
static int   capacitance_modeling  = ;
static float value = ;
static char  car = 'A';
static float bus_num = -1000.123;
static int   China_population = -;
static float x = 2.5, y = 4.7;
static int a = ;
//m=         (int)
//n=1.3456   (float)
static float test_n = 1.3456;
static int   test_m = ;

int main()
{

    int tmp =  / ;
    test_m = test_n *  + 0.5;
    test_n = test_m / 100.0;

    //x+y
    printf("类型转换is %f\n",x+a%*(int)(x + y)%/);
    printf("tmp is %d\n", tmp);
    printf("test_n is %f\n",test_n);

    while ()
    {
        getchar();
    }

    return ;
}