/in/foo.c: In function 'main':
/in/foo.c:6:23: error: expected ';' before 'if'
    6 |         scanf("%f",&x)
      |                       ^
      |                       ;
    7 |         if(x<0)
      |         ~~             
/in/foo.c:9:19: error: invalid suffix "x" on integer constant
    9 |                 y=3x+1;
      |                   ^~
/in/foo.c:5:13: warning: unused variable 'y' [-Wunused-variable]
    5 |     float x,y;
      |             ^