Compilare: user.cpp: In function ‘bigint add(bigint, bigint)’: user.cpp:34: warning: comparison between signed and unsigned integer expressions user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘bigint mul(bigint, bigint)’: user.cpp:55: warning: comparison between signed and unsigned integer expressions user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:119: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:120: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:123: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result