Compilare: user.cpp: In function ‘int main()’: user.cpp:26:24: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(!feof(si)&&('a'<=a&&a<='z')||('A'<=a&&a<='Z')) ^ user.cpp:15:23: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(si,"%c",&a); ^ user.cpp:31:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(si,"%c",&a); ^ user.cpp:41:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(si,"%c",&a); ^