CODEWITHSUNDEEP
cprintf
CH4B
CH4B

Reputation: 37

Why is my pow result always zero?

In my code, squaring the variable R always gives zero. It does not matter if it's pow(R, 2) or R*R. Why does that happen? (If I change it to float, it works, but I need it to be a double for the precision.)

This is the code:

int main () {

    double R,PI,a;
    PI = 3.14159;
    scanf(" %d", &R);
    a = PI * (pow(R,2));
    printf ( "A= %0.4d \n", a );

    return 0;

}

Upvotes: 1

Views: 122

Answers (1)

dbush
dbush

Reputation: 224917

You're using the wrong format specifier in scanf and printf.

The %d format specifier expects the address of an int for scanf, and an int for printf. You're instead passing in the address of a double and a double respectively. Using the wrong format specifiers invokes undefined behavior.

You need to use %lf in scanf and %f in printf for a double:

scanf("%lf", &R);
a = PI * (pow(R,2));
printf ( "A= %0.4f \n", a );

Upvotes: 2

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