Main.c: In function ‘main’:
Main.c:6:2: warning: implicit declaration of function ‘scanf_s’; did you mean ‘scanf’? [-Wimplicit-function-declaration]
    6 |  scanf_s("%d", &T);
      |  ^~~~~~~
      |  scanf
Main.c:15:14: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration]
   15 |    int len = strlen(a);
      |              ^~~~~~
Main.c:15:14: warning: incompatible implicit declaration of built-in function ‘strlen’
Main.c:2:1: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
    1 | #include<stdio.h>
  +++ |+#include <string.h>
    2 | 
Main.c:22:21: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses]
   22 |   for (int i = 0; i < 10 & flag == 1; i++)
      |                   ~~^~~~
/usr/bin/ld: /tmp/ccUL1JOv.o: in function `main':
Main.c:(.text.startup+0x20): undefined reference to `scanf_s'
collect2: error: ld returned 1 exit status