各位同学前辈，我这个代码运行显示正确，但是显示的都是乱码是怎么回事？

#include

int main()

{    char c = 97; 

  int n = c        //将c赋值给n  

 float f = c       //将c赋值给f

   double d = c     //将c赋值给d

   printf("%d\n",n);   

printf("%f\n",f);   

printf("%lf\n",d);

   return 0;   

} 

显示结果： 

/249/5117/8r7b/hello.c: In function 'main':
/249/5117/8r7b/hello.c:6:5: error: expected ',' or ';' before 'float'
    float f = c       //将c赋值给f
    ^
/249/5117/8r7b/hello.c:9:19: error: 'f' undeclared (first use in this function)
    printf("%f\n",f);
                  ^
/249/5117/8r7b/hello.c:9:19: note: each undeclared identifier is reported only once for each function it appears in
/249/5117/8r7b/hello.c:10:20: error: 'd' undeclared (first use in this function)
    printf("%lf\n",d);