Compilare: user.cpp: In function ‘void evaluare()’: user.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(str) && !isalpha(s[i])) ^ user.cpp:49:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<strlen(str)) evaluare(); ^ user.cpp: In function ‘int main()’: user.cpp:118:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie3.in","r",stdin); ^ user.cpp:119:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie3.out","w",stdout); ^ user.cpp:120:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",str); ^