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In c++ this code below shows an error:

expression must have integral or unscoped enum type
illegal left operand has type 'double'

is it possible to correct it without the need to use fmod?

# include <iostream>    
using namespace std;

int main()
{
    int x = 5, y = 6, z = 4;
    float w = 3.5, c;
    c = (y + w - 0.5) % x * y;   // here is the error
        cout << "c = " << c << endl;

    return 0;
}
Amida
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1 Answers1

0

You can use type casting to fix it :

c = ((int) (y + w - 0.5)) % x * y;

To clarify your response in the comments, changing c to type int still don't work as the part (y + w - 0.5) is not evaluated as int but as double. And modulus operation doesn't take that type as an argument.

Full modified code :

#include <iostream>
using namespace std;

int main()
{
    int x = 5, y = 6, z = 4;
    float w = 3.5, c; //c could still stayed as float
    c = ((int) (y + w - 0.5)) % x * y; //swapped out here
    cout << "c = " << c << endl;
}

Output : c = 24.

To be clear here, this is only a temporary fix for this case, when you know (y + w - 0.5) is going to have a clear integer value. If the value is something like 0.5 or 1.447, std::fmod is desirable.

Here's a post on type conversion rules in an expression regarding interaction between float/double and int/long long : Implicit type conversion rules in C++ operators

silverfox
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