scanf("%1d%1d",&a1,&a2); if(a1<2)switch(a2)18日11case 0:printf("ten\n");break;12case 1:printf("eleven\n");break;13case 2:printf("twelve\n");break;14case 3:printf("thirteen\n");break;15case 4:printf("fourteen\n") break;16case 5:printf(“fifteenin")ibreak;17case 6:printf(“sixteen\n");breakj18 case 7:printf("seventeenin");breaki19 case 8:printf("eighteen\n");break;20 case 9:printf("nineteen\n");break;21}2223elseswitch(a1) case case case case 2:printf3:printf4:printf5:printf ("twenty"("thirty"("forty")("fifty") ")break;";break;)break;);break; case case case case 6:printf7:printf8:printf9:printf ("sixty"(Tsevent("eighty("ninety ):break; y");break;");break;");break; 3435 switch(a2)3637白38 case e:break;case 1:printf("-one");break;39case 2:printf“-two");break;40case 3:printf( -three"ibreak;4142 case 4:printf("-four");breakj43 case 5:printf "-five);break;4445 case 6:printf case 7:printf -six"):break; -seven");break;case 8:printf -eight");break46case 9:pnintf("-nine")