Compilare: user.cpp: In function ‘int main()’: user.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<strlen(s);j++){ ^ user.cpp:11:21: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] {fscanf(f,"%d\n",&n); ^ user.cpp:13:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",s); ^