打印浮点数转字符串

#include<stdio.h>
void float2char(float,char*,int);
int main()
{
    char buffer[10];
    float2char(123.4567,buffer,10);
    printf("%f 转换成字符串 %s\n",123.4567,buffer);
    float2char(-654.321,buffer,10);
    printf("%f 转换成字符串 %s\n",-654.321,buffer);
    return 0;
}
void float2char(float slope,char*buffer,int n)  //浮点型数，存储的字符数组，字符数组的长度
{
    int temp,i,j;
    if(slope>=0)//判断是否大于0
        buffer[0] = '+';
    else
    {
        buffer[0] = '-';
        slope = -slope;
    }
    temp = (int)slope;//取整数部分
    for(i=0;temp!=0;i++)//计算整数部分的位数
        temp /=10;
    temp =(int)slope;
    for(j=i;j>0;j--)//将整数部分转换成字符串型
    {
        buffer[j] = temp%10+'0';
        temp /=10;
    }
    buffer[i+1] = '.';
    slope -=(int)slope;
    for(i=i+2;i<n-1;i++)//将小数部分转换成字符串型
    {
        slope*=10;
        buffer[i]=(int)slope+'0';
        slope-=(int)slope;
    }
    buffer[n-1] = '\0';
}

#include<stdio.h>
#include <math.h>
#include <stdlib.h>
 
const double eps = 1e-11;
  
void float_to_str(char *str,double num)
{
     int high;//float_整数部分  
     double low;//float_小数部分 
     char *start=str;
     int n=0;
     char ch[20];
     int i;
     high=(int)num;
     low=num-high;
     
     while(high>0){
         ch[n++]='0'+high%10;
         high=high/10;
     }
     
     for(i=n-1;i>=0;i--){
         *str++=ch[i];
     }
     
     num -= (int)num;
     double tp = 0.1;
     *str++='.';
     
     while(num > eps){//精度限制 
         num -= tp * (int)(low * 10);
         tp /= 10;
         *str++='0'+(int)(low*10);
         low=low*10.0-(int)(low*10);
     }
     *str='\0';
     str=start;
 }

 int main()
 {
     double a;
     while( ~scanf("%lf", &a) ) {
         char str[20];
         float_to_str(str,a);
         printf("%s\n\n",str);    
     }
     
 }
--------------------- 
作者：MingjaLee 
来源：CSDN 
原文：https://blog.csdn.net/lijiang1991/article/details/51251634