Dart语言赋值运算符

void main() { 
   var a = 12; 
   var b = 3; 

   a+=b; 
   print(a+=b : ${a}); 

   a = 12; b = 13; 
   a-=b; 
   print(a-=b : ${a}); 

   a = 12; b = 13; 
   a*=b; 
   print(a*=b' : ${a}); 

   a = 12; b = 13; 
   a/=b;
   print(a/=b : ${a}); 

   a = 12; b = 13; 
   a%=b; 
   print(a%=b : ${a}); 
}