Main.cc: In function ‘int main()’:
Main.cc:13:3: error: expected ‘;’ before ‘default’
default:v=1;
^~~~~~~
Main.cc:6:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d,%lf",&a,&b);
~~~~~^~~~~~~~~~~~~~~~