#include <stdio.h>
int main()
{
const float a = 1.8;
const float b = 32.0;
const float c = 273.16;
double hua,she,jue;
char ch[10];
int i=0,j=0;
printf("请输入华氏温度\n");
while(j != 1)
{
scanf("%lf", &hua);
ch = hua;
while(ch[i] != '\0')
{
if(ch[i] >= '0' && ch[i] <='9')
{
i++;
}
else
{
j = 1;
printf("您输入的温度有误\n");
break;
}
}
if(j != 1)
{
she = a * hua + b;
jue = she + c;
printf("华氏温度：%.2lf\n", hua);
printf("摄氏温度：%.2lf\n", she);
printf("绝对温度：%.2lf\n", jue);
}
}
return 0;
}
其实我也猜到是哪里错了，苦逼的是不知道怎么解决

ch = hua;

可以用sprintf函数将你的浮点数转换成字符串