1#include <stdlib.h>
 2#include <ctype.h>
 3
 4int atoi(const char *s)
 5{
 6	int n=0, neg=0;
 7	while (isspace(*s)) s++;
 8	switch (*s) {
 9	case '-': neg=1;
10	case '+': s++;
11	}
12	/* Compute n as a negative number to avoid overflow on INT_MIN */
13	while (isdigit(*s))
14		n = 10*n - (*s++ - '0');
15	return neg ? n : -n;
16}