/in/foo.cc:2:11: error: '::main' must return 'int'
 void main() 
           ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:5:24: warning: unused variable 'temp2' [-Wunused-variable]
 float a[5],avg,temp1=0,temp2=0,fc; 
                        ^~~~~
/in/foo.cc:5:32: warning: unused variable 'fc' [-Wunused-variable]
 float a[5],avg,temp1=0,temp2=0,fc; 
                                ^~