#include<stdlib.h>#include<ctype.h>longatol(constchar*s){longn=0;intneg=0;while(isspace(*s))s++;switch(*s){case'-':neg=1;case'+':s++;}/* Compute n as a negative number to avoid overflow on LONG_MIN */while(isdigit(*s))n=10*n-(*s++-'0');returnneg?n:-n;}