64                                2.     

//  : **+*+

cin    b  ;

discr = b*b -4**;

if ((discr > 0) && (sq_disc = sqrt(discr))) {

rooti = (-b + sq_disc) / (2 * a);

root 2 = (-b - sq_disc) / (2 * a) ;

}
else if (discr < 0) {// 

}
else

rooti = root2 = -b / (2 * a) ;

 sqrt ()     ,  -
        .   -
,         -
:

 =1.0, b = 4.0,  = 3.0
 =1.0, b = 2.0,  = 1.0
 =1.0, b = 1.0,  = 1.0

8.  C++ switch      case  
,     switch.

switch (i) {                       //""; :

case 0 case 1: ++hopeless;        //,

case 2 case 3: ++weak;            // ,

case 4 case 5: ++.fails; break;    //,

case  case 7: ++c_grades; break; //,

case 8 ++b_grades; break;         //,

case 9 ++a_grades; break;         //

default: cout  "  "  i  endl;

}

      i,  1.

9.       , -
,         . 
switch    ,   .

10.         ASCII-.
     count.c.    , -
     count.c.

/*  , , ,

    

*/

#include <stdio.h>