round.c

来自「语音CELP压缩解压源代码（C语音)」· C语言 代码 · 共 47 行

/* This routine takes in a floating point number and rounds it to */
/* the nearest integer. 					  */
int
round(afloat)
float afloat;
{
int rounded_int;

  /* this will truncate afloat */
  rounded_int = afloat;
  /* positive and negative numbers are handled differently */
  if (afloat < 0) 
  {
    /* if the fractional part is -.5 or less round down */
    if (afloat - rounded_int <= -.5) rounded_int--;
  }
  else
  {
    /* if the fractional part is .5 or greater round up */
    if (afloat - rounded_int >= .5) rounded_int++;
  }    
    
  return(rounded_int);
}


#ifdef TEST
#include <stdio.h>

main()
{
    float x,y,z;
    int i;

    x = -2.000001;
    y = -2.000000;
    z = -1.999999;
    for (i=0; i<16; i++) {
        printf("%f -> %d     %f -> %d     %f -> %d\n",
                x,round(x),y,round(y),z,round(z));
        x = x + 0.25;
        y = y + 0.25;
        z = z + 0.25;
        }
    }
#endif