/in/foo.c:2:1: warning: return type defaults to 'int' [-Wimplicit-int]
 main()
 ^~~~
/in/foo.c: In function 'main':
/in/foo.c:7:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
 {for(i=2;i<=m;i++)
  ^~~
/in/foo.c:10:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
     if(i==m)
     ^~