/in/foo.c: In function 'main':
/in/foo.c:8:5: error: expected ';' before 'if'
     if (x <= 0) {
     ^~
/in/foo.c:5:9: warning: unused variable 'sum' [-Wunused-variable]
     int sum = 0;
         ^~~
/in/foo.c:4:12: warning: unused variable 'i' [-Wunused-variable]
     int x, i;
            ^