/in/foo.c: In function 'main':
/in/foo.c:5:2: warning: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
gets(a);
^~~~
/in/foo.c:12:3: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
printf("%c",a[i]);
^~~~~~
/in/foo.c:12:3: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:12:3: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:15:3: warning: incompatible implicit declaration of built-in function 'printf'
printf("%c",b[i]);
^~~~~~
/in/foo.c:15:3: note: include '<stdio.h>' or provide a declaration of 'printf'
/tmp/ccekd937.o: In function `main':
foo.c:(.text.startup+0x20): warning: the `gets' function is dangerous and should not be used.