Compilare: user.c:3:6: warning: return type of ‘main’ is not ‘int’ [-Wmain] void main(void) ^ user.c: In function ‘main’: user.c:16:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(!(x[i]>='a'&&x[i]<='z'||x[i]>='A'&&x[i]<='Z')) ^ user.c:19:20: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(x[i]>='a'&&x[i]<='z'||x[i]>='A'&&x[i]<='Z') ^ user.c:10:8: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(x,1000,f); ^ In file included from /usr/include/stdio.h:934:0, from user.c:1: In function ‘fgets’, inlined from ‘main’ at user.c:10:8: /usr/include/i386-linux-gnu/bits/stdio2.h:253:2: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^