使用int误差进行浮点变量计算

Question

I run the following code:

// Example program
#include <iostream>
#include <string>
using namespace std;
int main()
{
  int x=4,y=2,z=11;
  float p;
  p=7+z/y-x*2;
  cout<<p;
  return 0;
}

The x, y, z is declared as integer. Why the p get an int while p is declared as float?

Thanks.

Answer 1

If a and b are integers then result of a/b will always be integer, not float. Dividing result is just truncated to integer value and float part is thrown away.

In expression 7+z/yx*2 only integer variables are used, that is why result is also integer.

As an option you can cast one of the operands on right side to float, then whole expression will be threated as float:

7+z/(float)y-x*2

Answer 2

pls change your integer datatype to float so u got

#include <iostream>
#include <string>
using namespace std;
int main()
{
  float x=4,y=2,z=11;
  float p;
  p=7+z/y-x*2;
  cout<<p;
  return 0;
}