8.7 checking.c
Posted eisnull
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了8.7 checking.c相关的知识,希望对你有一定的参考价值。
// checking.c -- 输入验证
#include <stdio.h>
#include <stdbool.h>
// 验证输入是一个整数
long get_long(void);
// 验证范围的上下限是否有效
bool bad_limits(long begin, long end,
long low, long high);
// 计算a~b之间的整数平方和
double sum_squares(long a, long b);
int main(void)
{
const long MIN = -10000000L; // 范围的下限
const long MAX = +10000000L; // 范围的上限
long start; // 用户指定的范围最小值
long stop; // 用户指定的范围最大值
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 then +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(start, 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 (enter 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 = getchar()) != '\n')
putchar(ch); // 处理错误输入
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;
}
以上是关于8.7 checking.c的主要内容,如果未能解决你的问题,请参考以下文章
Linux内存从0到1学习笔记(8.7 DMA-BUF代码解读)