Compilare: user.c:3:1: warning: return type defaults to ‘int’ [enabled by default] main() ^ user.c: In function ‘main’: user.c:18:16: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if((c >= 'a')&&(c <= 'z')||(c >= 'A')&&(c <= 'Z')) ^ user.c:29:19: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (((x >= 'a')&&(x <= 'z')||(x >= 'A')&&(x <= 'Z'))&& nc) ^ user.c:17:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%c",&c); ^ user.c:29:43: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (((x >= 'a')&&(x <= 'z')||(x >= 'A')&&(x <= 'Z'))&& nc) ^