Main()//main is written incorrectly.

{

int？ a = 0；

Floating? b = 1. 1245 f； //The data is double by default, plus the floating-point flag f.

Double? c = 23.5454

Printf ("\ nThree types of data are: plastic (%d), single precision (%f), double precision (%lf)\n", a, b and c); //the newline character dropped n.

a =(int)b；

Printf ("\ nConvert single-precision data b to integer data (int)b=%d\n", (int) b);

a =(int)c；

Printf ("\ nConvert single-precision data c into integer data (int)c=%d\n", (int) c);

a = 2；

b =(float)a；

Printf ("\ nConvert integer data a to single-precision data (float)a=%f\n", b);

c =(double)a；

Printf ("\ nConvert integer data a into double-precision data (a =% lf \ n", c);

Return? 0;

}