/in/foo.c: In function 'isPalindrome':
/in/foo.c:10:25: warning: implicit declaration of function 'malloc' [-Wimplicit-function-declaration]
     int* digits = (int*)malloc(digitCount * sizeof(int));
                         ^~~~~~
/in/foo.c:10:25: warning: incompatible implicit declaration of built-in function 'malloc'
/in/foo.c:10:25: note: include '<stdlib.h>' or provide a declaration of 'malloc'
/in/foo.c:24:5: warning: implicit declaration of function 'free' [-Wimplicit-function-declaration]
     free(digits);
     ^~~~
/in/foo.c:24:5: warning: incompatible implicit declaration of built-in function 'free'
/in/foo.c:24:5: note: include '<stdlib.h>' or provide a declaration of 'free'
/in/foo.c: In function 'main':
/in/foo.c:31:5: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
     scanf("%d", &num);
     ^~~~~
/in/foo.c:31:5: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:31:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:34:9: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
         printf("Yes\n");
         ^~~~~~
/in/foo.c:34:9: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:34:9: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:36:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("No\n");
         ^~~~~~
/in/foo.c:36:9: note: include '<stdio.h>' or provide a declaration of 'printf'