/in/foo.cc: In function 'int main()':
/in/foo.cc:8:11: error: expected ')' before ';' token
   if(i=100;i<1000;i++)
           ^
/in/foo.cc:8:11: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
/in/foo.cc:8:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if(i=100;i<1000;i++)
   ^~
/in/foo.cc:8:12: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
   if(i=100;i<1000;i++)
            ^
/in/foo.cc:8:13: warning: statement has no effect [-Wunused-value]
   if(i=100;i<1000;i++)
            ~^~~~~
/in/foo.cc:8:22: error: expected ';' before ')' token
   if(i=100;i<1000;i++)
                      ^
/in/foo.cc:6:7: warning: unused variable 'x' [-Wunused-variable]
   int x,y,z,a;
       ^
/in/foo.cc:6:9: warning: unused variable 'y' [-Wunused-variable]
   int x,y,z,a;
         ^
/in/foo.cc:6:11: warning: unused variable 'z' [-Wunused-variable]
   int x,y,z,a;
           ^
/in/foo.cc:6:13: warning: unused variable 'a' [-Wunused-variable]
   int x,y,z,a;
             ^
/in/foo.cc:20:1: error: expected '}' at end of input
 } 
 ^