#define LONG_MAX 2147483647L #define LONG_MIN
(-2147483647L-1L) #includelong strtol ( char
nptr; unsigned long acc; unsigned char c;
unsigned long cutoff; int neg = 0,any, cutlim; //判断正负号
do{ c = *s++; } while (c==' '); if (c ==
'-') { neg = 1; c = *s++;
} else if (c == '+') c = *s++;
//判断进制数 if ((base == 0 || base == 16) &&
c == '0' && (*s == 'x' || *s == 'X'))
{ c = s[1]; s += 2; base =
16; } if (base == 0) base = c == '0'
? 8 : 10; //溢出处理 cutoff = neg ? -(unsigned long)
LONG_MIN : LONG_MAX; cutlim = cutoff % (unsigned long)
base; cutoff /= (unsigned long) base; for (acc =
0, any = 0;; c = *s++) { if
(c>='0'&&c<='9') c -= '0';
else if
((c>='A'&&c<='Z')||(c>='a'&&c<='z'))
c -= (c>='A'&&c<='Z') ? 'A' - 10 : 'a' -
10; else break; if
((int) c >= base) break; if (any
< 0 || acc > cutoff || acc == cutoff && (int) c >
cutlim) any = -1; else
{ any = 1; acc *= base;
acc += c; } }
//超过范围则输出range error if (any < 0) {
// acc = neg ? LONG_MIN : LONG_MAX; //errno =
else if (neg) acc = -acc; if (endptr !=
0) *endptr = any ?(char *) ( s - 1) : (char *) nptr;
return acc; } int main(){ char*nptr="-0x12G
00,";char *endptr[100];int base=0; long n= strtol (
nptr, endptr, base) ;
printf("n=%ldnendptr=%sn",n,*endptr); }