Printing decimal using float,double in c++

Question

I have been trying to print decimals by storing the variables into float and double but I am not getting the desired output. what don't I understand about these data types?

Following is my code:

int main(){
    double s = 0;
    float r = 1 / 4;
    cout << r << endl;
    cout << pow((1 - s), 2) << endl;
    cout << (2 + s) << endl;
    cout << (1 / 4) * (pow((1 - s), 2)) * (2 + s) << endl;
    return 0;
}

Output:

The first line should be 0.25 and the last should be 0.5.

Storing the value into a float or double won't help if you *compute* the value in integer arithmetic. — user2357112, Jul 13 '17 at 23:44

score 2 · Accepted Answer · answered Jul 13 '17 at 23:45

You are doing integer math. Integer one divided by integer four is rounded down to zero.

You need to tell the compiler that your number literals are floating point values.

float r = 1.0 / 4.0;
cout << r << endl;
cout << pow((1.0 - s), 2) << endl;
cout << (2.0 + s) << endl;
cout << (1.0 / 4.0) * (pow((1.0 - s), 2)) * (2.0 + s) << endl;

Printing decimal using float,double in c++

1 Answers1