C/math.h/lround

lround: returns the value of arg rounded to the nearest long integer

<source lang="cpp">

//Declaration: long int lroundf(float arg);

              long int lround(double arg); 
              long int lroundl(long double arg);  

// Values precisely between two values, such as 3.5, are rounded up.</p>

 #include <math.h>
 #include <stdio.h>
 int main(void)
 {
   double val = 1.0;
   do {
     printf("%f %f\n", val, lround (val));
     val++;
   } while (val<11.0);
   return 0;
 }
        

/* 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000.000000 6.000000 81386476629122498000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000.000000 7.000000 81386476629122513000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000.000000 8.000000 81386476629122528000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000.000000 9.000000 81386476629122542000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000.000000 10.000000 8138647662912255700000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000.000000

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      </source>