C指针类型转换

Question

float fNum = 12.3;
int *pF = (int *)&fNum;
printf("fNum:%f pF:%d \n", fNum, *pF);
*pF = 233;
printf("fNum:%f pF:%d \n", fNum, *pF);

return 0;

The result is like this

fNum:12.300000 pF:1095027917 
fNum:0.000000 pF:233 

I want to know why the result like this? Don't fNum & *pf point to the same memory?

Answer 1

To start with, the variable fNum doesn't point to anything. It's the actual value.

And a floating point number is not the same as an integer. The bit-patterns in memory are very different for a floating point number.

Answer 2

fNum contains floating point binary presentation of 12.3 . So when your print the content of the fNum memory as integer you will get the translation this binary set as decimal value