Main.cc: In function ‘void dem(int, int, int*, int*)’:
Main.cc:14:12: error: return-statement with a value, in function returning 'void' [-fpermissive]
return dem;
^~~
Main.cc: In function ‘int main()’:
Main.cc:26:9: error: ‘m’ was not declared in this scope
dem(m,n,a,b);
^
Main.cc:21:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&n);
~~~~~^~~~~~~~~