What is the difference?

Question

#include <iostream>
using namespace std;

int main()
{
int a = 30;
int b = 12;
float c = a / b;

cout << c;

return 0;
}

The output is 2

But if I exchange one(or just two) of the data types of a and b into float, I get an output 2.5.
What is the difference? I mean that I have already declared c is an float, why the data type of a and b change the result. Thanks.

Answer 1

Result of a/b results integer value because a and b are defined an integer.
To get float value as result of a/b, you can typecast the result to float as-

float c=(float)(a/b);

Answer 2

Sorry, mistakenly I put extra parenthesis,
You have to typecast atleast one integer variable as float to get the floating pt number.
eg.
float c=(float)a/b;

Answer 3

When you divide two integers, you are performing integer division, so only the integer part of the calculation is retained, and the decimal part is discarded.

Answer 4

I don't know C++, but I do know that in some languages when the / operator takes two ints as arguments, it does an integer division (that is, returns an integer). For example, if you do float c=a/(float)b it returns the expected result.

Answer 5

@Sachin If you do that, you are still making an integer division because you are passing two integers to the / operator, so it doesn't change the output.

Answer 6

Thank you for all the answers. I got it.☺