使用gcc编译时出现错误：警告：格式指定类型为'int *'，但参数的类型为'double *'

这是我用C语言编写的第一个程序，请当心。

我试图获取用户输入的温度之间的转换，并使用开关盒来计算转换后的温度。当在Mac上尝试使用gcc对其进行编译时，我的以下程序会抛出此类错误：

convertTemp.c:17:20: warning: format specifies type 'int *' but the argument has type 'double *' [-Wformat]
      scanf ("%d", &Celcius);
              ~~   ^~~~~~~~
              %lf
convertTemp.c:21:72: warning: format specifies type 'int' but the argument has type 'double' [-Wformat]
      printf ("The converted temperature of %d in Fahreight is: %d\n", Celcius, Fahr);
                                            ~~                         ^~~~~~~
                                            %f
convertTemp.c:21:81: warning: format specifies type 'int' but the argument has type 'double' [-Wformat]
      printf ("The converted temperature of %d in Fahreight is: %d\n", Celcius, Fahr);
                                                                ~~              ^~~~
                                                                %f
convertTemp.c:25:20: warning: format specifies type 'int *' but the argument has type 'double *' [-Wformat]
      scanf ("%d", &Fahr);
              ~~   ^~~~~
              %lf
convertTemp.c:29:70: warning: format specifies type 'int' but the argument has type 'double' [-Wformat]
      printf ("The converted temperature of %d in Celcius is: %d\n", Fahr, Celcius);     
                                            ~~                       ^~~~
                                            %f
convertTemp.c:29:76: warning: format specifies type 'int' but the argument has type 'double' [-Wformat]
      printf ("The converted temperature of %d in Celcius is: %d\n", Fahr, Celcius);     
                                                              ~~           ^~~~~~~
                                                              %f
6 warnings generated.

代码：

#include <stdio.h>

int main (void)
{
  int choice;
  double Celcius, Fahr;

  printf ("Do you want to convert from C to F (1) or from F to C(2))?");

  scanf ("%i", &choice);


  switch(choice)
  {
    case 1:
      printf ("Please type the temp in Celcius");
      scanf ("%d", &Celcius);

      Fahr = (Celcius * 9) / 5;
      Fahr += 32;
      printf ("The converted temperature of %d in Fahreight is: %d\n", Celcius, Fahr);

    case 2:
      printf ("Please type the temp in Fahrenheit");
      scanf ("%d", &Fahr);

      Celcius = (Fahr - 32) * 5;
      Celcius /= 9;
      printf ("The converted temperature of %d in Celcius is: %d\n", Fahr, Celcius);

  }

  return 0;

}