Compilare: user.cpp: In function ‘int main()’: user.cpp:36:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < min(first.size(), second.size()); ++i) ^ user.cpp:39:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i != min(first.size(), second.size())) ^ user.cpp:48:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = k ; j < first.size(); ++j, ++i) ^ user.cpp:58:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = k; j < second.size(); ++j, ++i) ^ user.cpp:77:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < min(first.size(), second.size()); ++i, --nr1, --nr2) { ^ user.cpp:82:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i != min(first.size(), second.size())) ^ user.cpp:17:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d\n", &n); ^ user.cpp:20:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%c", &s[i]); ^