Eroare de compilare: user.cpp: In function ‘void read_input()’: user.cpp:23: error: ‘strlen’ was not declared in this scope user.cpp:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void euler()’: user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp:73: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:79: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:80: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:85: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result