void runtime_call(){
	char a;
	char b;
	printf("input connection mode\n");
	scanf("%c%c",&a,&b);
	for(;a!='q';){
		if(a=='1'){
			//sync
			sync_client();
		}
		else if(a=='2'){
			//trans
			trans_client();
		}
		else if(a=='3'){
			//http
		}
		printf("input connection mode again\n");
		scanf("%c%c",&a,&b);
	}
	send(sockad,&a,1,0);
}