Using while loops instead of pow: What does this error mean? - c

Question

I am attempting to create some code with C programming that can show a number to a certain power with both values specified by the user. I want to use pow for the first part and a while loop for the second. However, I've confronted an error with this current code that I cannot seem to get rid of.
Here is ther error that I am unfamiliar with:
error: invalid operands to binary * (have ‘int (*)(int, int)’ and ‘int’)
result2 = result2 * base;
I've tried looking into other questions with the same error, but they differ so much that I cannot understand.
I've tried researching into "long" but I have not been experienced with it yet through my C textbook, so I would like to refrain from using it if possible.
#include <stdio.h>
#include <math.h>
int result2(int base, int exponent);
int main(void)
{
double base;
double exponent;
double result1;
puts("Please enter a value as the base and another as the exponent.");
scanf("%lf%lf", &base, &exponent);
result1 = pow(base, exponent);
printf("Library solution: %lf\n", result1);
printf("My solution: %d\n", result2(base, exponent));
}
int result2(int base, int exponent)
{
int i;
for(i=1; i<=exponent; i++)
{
result2 = result2 * base;
}
return;
}
I would like to be able to calculate the equation properly using both methods with the user's values. However, with this error, I just cannot seem to get past and achieve that. Thank you.

Answer 1

int result2(int base, int exponent)
{
int i;
for(i=1; i<=exponent; i++)
{
result2 = result2 * base;
}
return;
}
result2 is the name of your function. Rather than using it like a variable that can accumulate the results of the loop, you should create a variable to do that job. Then return the value of the variable at the end.
int result2(int base, int exponent)
{
int i;
int result = 1;
for(i=1; i<=exponent; i++)
{
result = result * base;
}
return result;
}
Better yet, give the function a different name. result2 sounds like the name of a variable. The function should be named something that indicates what it does. Since pow is taken, how about power?
int power(int base, int exponent)
{
int result = 1;
for (int i=1; i<=exponent; i++)
{
result *= base;
}
return result;
}
Some other small improvements are declaring int i inside the for loop, and using result *= base as shorthand for result = result * base.

Answer 2

i made a few modifications to your code.
1) Renamed funtion result2 to my_exp. result2 sound like a variable.
2) Modify types for funtion my_exp to int to be consistent with the variables types of main.
3) Add a variable result in my_exp to store the partial result of for loop.
4) Declared i inside for declaration.
5) call pow and my_exp inside printf and remove result1 is not necesary anymore.
6) Changed how result is calculed to a more compact way.
most of those changes are cosmetic except for types changes.
int my_exp(int base, int exponent);
int main(void)
{
int base;
int exponent;
puts("Please enter a value as the base and another as the exponent.");
scanf("%i", &base);
scanf("%i", &exponent);
printf("Library solution: %i\n", pow(base, exponent));
printf("My solution: %i\n", my_exp(base, exponent));
}
int my_exp(int base, int exponent)
{
//int i;
int result;
result = 1;
for(int i=1; i<=exponent; i++)
{
result *= base;
}
return result;
}