int main(void)
{
FILE *inp, *outp;
int numIn, status;
/*Open files*/
inp = fopen("perfect.dat", "r");
outp = fopen("perfect.out", "w");
status = fscanf(inp, "%d", &numIn);
/*While there are no errors, output results to output file*/
while(status == 1)
{
if (numIn == sumOfDivisors(numIn))
fprintf(outp, "%d is a perfect number\n", numIn);
else
fprintf(outp, "%d is not a perfect number\n", numIn);
status = fscanf(inp, "%d", &numIn);
}
if (status != EOF)
printf("There was an error in the input. \n\nExiting.");
/*Close files*/
fclose(inp);
fclose(outp);
return(0);
}
int main(int argc, char **argv)
{
unsigned int result = 0;
printf("220 -> %d\n", sumOfDivisors(220));
printf("284 -> %d\n", sumOfDivisors(284));
for (int i = 0; i < 10000; i++)
{
unsigned int rv = sumOfDivisors(i);
if (sumOfDivisors(rv) == i)
{
if (i < rv)
result += i + rv;
}
}
printf("%d\n", result);
return 0;
}
void main()
{
int sums[9999];
int i, count;
for (i = 0; i < 9999; ++i)
sums[i] = sumOfDivisors(i + 1);
for(i = 0,count = 0;i < 9999;i++)
if((sums[i] < 9999) && (sums[i] > (i + 1)) && (sums[sums[i] - 1] == (i + 1)))
count += (i + 1) + sums[i];
printf("solution: %d\n", count);
}
int main() {
assert(sumOfDivisors(220) == 284);
int number1, number2;
scanf("%d %d", &number1, &number2);
if (amicable_numbers(number1, number2)) printf("YES\n");
else printf("NO\n");
return 0;
}
/* returns array of all abundant nums less than max parameter,
outputs size of resulting array to size parameter */
unsigned int *abunNums(unsigned int max, unsigned int *size)
{
unsigned int *out = NULL;
unsigned int c;
unsigned int n = 0; /* array size representer */
for (c=12 ; c<max ; c++) // 12 is smallest abundant num
if (sumOfDivisors(c)>c || c%12==0) {
n+=1;
out = (unsigned int *)realloc(out,sizeof(unsigned int)*n);
out[n-1] = c;
}
*size = n;
return out;
}
int main(int argc, char const *argv[])
{
int amicableSum = 0;
int limit = 10000;
bool nums[10000] = {false};
bool isSumSuitable;
bool isAmicable = false;
printf("\n");
int iSum = 0;
int i;
for (i = 2; i < limit; i++)
{
if (nums[i] == false)
{
iSum = sumOfDivisors(i);
isSumSuitable = (iSum != i) && (iSum < limit) && (iSum > 1);
if (isSumSuitable)
{
isAmicable = checkAmicable(i, iSum);
}
}
if (isAmicable)
{
printf("%d and %d are an amicable pair\n", i, iSum);
nums[i] = true;
nums[iSum] = true;
amicableSum += i + iSum;
}
isAmicable = false;
}
printf("\nSum of amicable numbers under %d:\n\t%d\n", limit, amicableSum);
return 0;
}
bool isAbundant(int n)
{
return (sumOfDivisors(n) > n);
}
bool checkAmicable(int n, int m)
{
int mSum = sumOfDivisors(m);
bool isAmicable = mSum == n;
return isAmicable;
}
bool amicable_numbers(int a, int b) {
return ((sumOfDivisors(a) == b) && (sumOfDivisors(b) == a));
}
