taler.cpp: In function 'int main()': taler.cpp:49: warning: comparison between signed and unsigned integer expressions taler.cpp:66: warning: format '%d' expects type 'int', but argument 2 has type 'long long int' taler.cpp:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result taler.cpp:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result taler.cpp:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result