why does different data type b result in different consequence ?

Question

I am a new C++ learner and write a small code.
But I am confused the results are different.
for example,
N N^2 N^2
-----------------------
0 0 0
5 24 25
10 99 100

Thank you for your patient.

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;

int Square(int);
int Cubic(int);

int main()
{
int i, C;
cout << " N N^2 N^2" << endl;
cout << "-----------------------" << endl;

for (i = 0; i <= 10; i++)
{
C = 5 * i;
cout << setw(6) << C << " " << setw(6) << Square(C) << " " << setw(6) << Cubic(C);
cout << endl;
}
cout << "-----------------------" << endl;
return 0;
}

int Square(int c)
{
int b;
b = pow(c, 2);
return b;
}

int Cubic(int c)
{
float b;
b = pow(c, 2);
return b;
}

N N^2 N^2
-----------------------
0 0 0
5 24 25
10 99 100
15 224 225
20 399 400
25 624 625
30 899 900
35 1225 1225
40 1599 1600
45 2024 2025
50 2499 2500
-----------------------

Answer 1

I test ran your code in Code Playground, three times, and all the time the outputs of Square and Cubic are the same. Also I am a bit confused why you use a float in Cubic yet you declared it to return int.

If you have different outputs on your side then I guess it was probably a side effect of the rounding that took place as you narrow from float → int. A side note, isn't Cubic supposed to return pow(c, 3) instead?

Hth, cmiiw

Answer 2

You're welcome, and let's hope someone come in later who can explain the odds, because IIRC Code Playground also uses MinGW, as the server is running Windows server O/S, I could be wrong though : )

Answer 3

I mean when I use int b, for example of 5^2 ,I get 24. But the type of b is float, the answer is 25. The later answer is right. I just dont know the reason. Maybe just rounding.

Sorry, I forget mention that I use visual studio code and MinGW. Yes, you are right, the answer is the same bye using Code Playground.

Thanks very much.