小数字符数组转换为浮点数

 编写程序把一个保存有二进制小数的字符数组转换为浮点数

 

#include <stdio.h>
#include <stdlib.h>

const int MAX=10;

float convert(const char* str)
{
  float sum1 = 0.0;
  float sum2 = 0.0;
  int i = 0;
  int idx = 0;
  int len = strlen(str);
  
  while(str[idx]!='.')
     idx++;
  
   printf("len is %d, index is %d\n", len, idx);
   i = idx;
   while(i--)
       sum1 = sum1*2 + (str[i]-'0');
     
   i = len-1;
  while(i>idx)
   {
     sum2 = (sum2 + (str[i]-'0'))*0.5;
     i--;
   }
   printf("sum1 is %f, sum2 is %f\n", sum1, sum2);
   return (sum1+sum2);
}

int main(int argc, char *argv[])
{
  float ret = 0.0;
  char str[MAX];
  while(1)
  {
   printf("Please input the str:\n");
   scanf("%s", str);
   ret = convert(str);
   printf("%f\n",ret);
  }
  system("PAUSE");    
  return 0;
}