将一个字符串转换成数字
2015-07-28 11:27
405 查看
/*
function:将输入的字符串转换成数字;默认为double型
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
double convert(char str[],int n);
int main(void)
{
char str[40];
double s;
scanf_s("%s", str, sizeof(str));
s = convert(str,40);
printf("%.40lf\n", s);
system("pause");
return 0;
}
double convert(char str[],int n)
{
double sum = 0.0;
int sign;
int count;
int scount;
int power = 1;
int p;
double spower = 0.1;
double s;
if (str[0] == '-')
{
sign = -1;
}
else
{
sign = 1;
}
for (int i = 0; i < n; i++)
{
if (str[i] == '\0')
{
p = i;
count = i;
scount = i;
break;
}
}
for (int i = 0; i < n; i++)
{
if (str[i] == '.')
{
count = i;
scount = i;
break;
}
}
while (count - 1 >= 0 && str[count - 1] >= '0' && str[count - 1] <= '9')
{
s = (double)(str[count - 1] - '0')*power;
sum += s;
count--;
power *= 10;
}
while (scount + 1 < p && str[scount + 1] >= '0' && str[scount + 1] <= '9')
{
s = (double)(str[scount + 1] - '0')*spower;
sum += s;
scount++;
spower /= 10;
}
sum *= sign;
return sum;
}
function:将输入的字符串转换成数字;默认为double型
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
double convert(char str[],int n);
int main(void)
{
char str[40];
double s;
scanf_s("%s", str, sizeof(str));
s = convert(str,40);
printf("%.40lf\n", s);
system("pause");
return 0;
}
double convert(char str[],int n)
{
double sum = 0.0;
int sign;
int count;
int scount;
int power = 1;
int p;
double spower = 0.1;
double s;
if (str[0] == '-')
{
sign = -1;
}
else
{
sign = 1;
}
for (int i = 0; i < n; i++)
{
if (str[i] == '\0')
{
p = i;
count = i;
scount = i;
break;
}
}
for (int i = 0; i < n; i++)
{
if (str[i] == '.')
{
count = i;
scount = i;
break;
}
}
while (count - 1 >= 0 && str[count - 1] >= '0' && str[count - 1] <= '9')
{
s = (double)(str[count - 1] - '0')*power;
sum += s;
count--;
power *= 10;
}
while (scount + 1 < p && str[scount + 1] >= '0' && str[scount + 1] <= '9')
{
s = (double)(str[scount + 1] - '0')*spower;
sum += s;
scount++;
spower /= 10;
}
sum *= sign;
return sum;
}
相关文章推荐
- 数据库链接字符串查询网站
- Flex字符串比较 还有Flex字符串操作
- Ruby中创建字符串的一些技巧小结
- ASP下经常用的字符串等函数参考资料
- 将字符串小写转大写并延时输出的批处理代码
- 将字符串转换成System.Drawing.Color类型的方法
- Lua和C语言的交互详解
- Lua源码中字符串类型的实现
- Lua性能优化技巧(四):关于字符串
- 字符串聚合函数(去除重复值)
- 总结的5个C#字符串操作方法分享
- sqlserver中求字符串中汉字的个数的sql语句
- sql server字符串非空判断实现方法
- VBS的字符串及日期操作相关函数
- C#实现将千分位字符串转换成数字的方法
- jquery 删除字符串最后一个字符的方法解析
- oracle SCN跟TIMESTAMP之间转换
- C#将制定目录文件名转换成大写的方法
- PowerShell实现在字符串中查找大写字母
- linux----->shell高级编程----1