How do I find the index of a character within a string in C?

Question

Suppose I have a string \"qwerty\" and I wish to find the index position of the e character in it. (In this case the index would be 2)

Answer 1

What about:

char *string = "qwerty";
char *e = string;
int idx = 0;
while (*e++ != 'e') idx++;

copying to e to preserve the original string, I suppose if you don't care you could just operate over *string