Compilare: user.cpp: In function ‘void ex(char*, FILE*)’: user.cpp:28:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(strlen(b)<n) fprintf(fout,"-1\n"); ~~~~~~~~~^~ user.cpp: In function ‘int main()’: user.cpp:38:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&T); ^ user.cpp:41:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",a); ^