# Totient Calculator in C

Rewrote my totient calculator in C. It’s pretty much a direct translation of the excrement I wrote in Rust. Be gentle, there are obvious points that I miss completely in C that veterans in the ancient language would scoff heartily about. I don’t yet know what the hell a struct is for or the extents of threading. All in good time.

So here’s my uncommented and fully unnecessary data type usage.

Behold:

```
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
unsigned long int gcd(unsigned long int e, unsigned long int f);
unsigned long int tot(unsigned long int t);
int main(int argc, char *argv[])
{
if (argc < 3 || argc > 3) { printf("Usage: %s first second\n",
argv[0]); exit(0); }
unsigned long int a = strtol(argv[1], NULL, 10);
unsigned long int b = strtol(argv[2], NULL, 10);
unsigned long int i;
if (a > b) { printf("First must be lower than second.\n"); }
for ( i = a ; i <= b ; i++ )
{
printf("%d, %d\n", i, tot(i));
}
exit(0);
}
unsigned long int gcd(unsigned long int a, unsigned long int b)
{
unsigned long int c;
while ( a != 0 )
{
c = a;
a = b % a;
b = c;
}
return b;
}
unsigned long int tot(unsigned long int t)
{
unsigned long int y = 0;
unsigned long int o = t;
while ( t != 0 )
{
if (gcd(o, t) == 1)
{
y++;
}
t--;
}
return y;
}
```