Compilare: user.cpp: In function ‘void ex(char*, FILE*)’: user.cpp:29:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(strlen(b)<n) fprintf(fout,"-1\n"); ~~~~~~~~~^~ user.cpp:10:9: warning: unused variable ‘d’ [-Wunused-variable] int d=-1; ^ user.cpp: In function ‘int main()’: user.cpp:40:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&T); ^ user.cpp:43:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",a); ^