cezar.cpp: In function 'int main()': cezar.cpp:16: warning: NULL used in arithmetic cezar.cpp:11: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result cezar.cpp:14: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result