关于 c primer plus 8.7程序的疑问
书上的代码如下：#include<stdio.h>
#include<stdbool.h>
long gat_long(void);
bool bad_limits(long begin, long end,
long low, long high);
double sum_squares(long a, long b);
int main(void)
{
const long MIN = -10000000L;
const long MAX = +10000000L;
long start;
long stop;
double answer;
printf("This program computes the sum of the squares of "
"integers in a range.\nThe lower bound should not "
"be less than -10000000 and\nthe upper bound "
"should not be more than +10000000.\nEnter the "
"limits(enter 0 for both limits to quit):\n "
"lower limit: ");
start = get_long();
printf("upper limit: ");
stop = get_long();
while (start != 0 || stop ! = 0)
{
if (bad_limits(stare, stop, MIN, MAX))
printf("please try again.\n");
else
{
answer = sum_squares(start, stop);
printf("The sum of the squares of the integers ");
printf("from %ld to %ld is %g\n",start, stop, answer);
}
printf("Enter the limits (entre 0 for both "
"limits to quit) :\n");
printf("lower limit: ");
start = get_long();
printf("upper limit: ");
stop = get_long();
}
printf("Done.\n");
return 0;
}
long get_long(void)
{
long input;
char ch;
while (scanf("%ld",&input) != 1)
{
while ((ch = getchat() != '\n')
putchar(ch);
printf(" is not an integer.\nplease enter an ");
printf("integer value, such as 25, -178, or 3: ");
}
return input;
}
double sum_squares(long a, long b)
{
double total = 0;
long i;
for (i = a; i <= b; i++)
total += (double) i * (double) i;
return total;
}
bool bad_limits(long begin, long end,
long low, long high)
{
bool not_good = false;
if(begin > end)
{
printf("%ld isn't smaller than %ld.\n", begin, end);
not_good = true;
}
if (begin > low || end < low)
{
printf("Values must be %ld or greater.\n",low);
not_good = true;
}
if (begin > high || end > high)
{
printf("Values must be %ld or less.\n",high);
not_good = true;
}
return not_good;
}
问题1：关于long get_long(void)这个函数里面的 第二个while什么时候会用到？或者说什么条件下会出发？不是很清楚这个函数的流程....
