Main.c: In function ‘main’:
Main.c:5:10: error: ‘i’ undeclared (first use in this function)
    5 |     for (i = 1; i < T; i++) {
      |          ^
Main.c:5:10: note: each undeclared identifier is reported only once for each function it appears in
Main.c:4:5: warning: ignoring return value of ‘scanf’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
    4 |     scanf("%d", &T);
      |     ^~~~~~~~~~~~~~~
Main.c:6:9: warning: ignoring return value of ‘scanf’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
    6 |         scanf("%d", &a);
      |         ^~~~~~~~~~~~~~~