CODEWITHSUNDEEP
cexponent
FireyThief
FireyThief

Reputation: 13

Having trouble with pow() in C

I am currently reading an online version of Stephen Kochan's "Programming in C (3rd Edition)." One of the activities involves evaluating an equation,

Write a program that evaluates the following expression and displays the results (remember to use exponential format to display the result): (3.31 x 10-8 x 2.01 x 10-7) / (7.16 x 10-6 + 2.01 x 10-8)

When I attempt to do this, the output is always 0.0000. Here is my code.

#include <stdio.h>
int main (void) {
float result;
    result = (3.31 * pow(10,-8) * 2.01 * pow(10,-7)) / (7.16 * pow(10,-6) + 2.01 * pow(10, -8));
    printf ("%f", result);
    return 0;
}

If I am doing anything wrong, please point it out. If you have any tips, please say so.

Upvotes: 0

Views: 609

Answers (2)

Chisom Ogueji
Chisom Ogueji

Reputation: 1

Use %e to get an exponent result value as instructed.

int main (void)
{
float i;
float j;
float result;
result = i / j;
i = 3.31 * 10 -8 * 2.01 * 10 -7;
j = 7.16 * 10 -6 + 2.01 * 10 -8;
printf("%e", i, j, result);

return 0;
}

Upvotes: -1

John Perry
John Perry

Reputation: 2678

You must #include <math.h>

Also, change to this:

printf ("%e\n", result);

You should probably also have

double result;

because pow() returns a double.

Upvotes: 5

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