Compilare: user.cpp: In function ‘int reference(int, int)’: user.cpp:24:9: warning: unused variable ‘i’ [-Wunused-variable] int i = 0; ^ user.cpp: In function ‘int main()’: user.cpp:69:10: warning: unused variable ‘formula’ [-Wunused-variable] char formula[300]; ^ user.cpp:65:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.in", "rt", stdin); ^ user.cpp:66:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.out", "wt", stdout); ^ user.cpp: In function ‘void eval(char*, int, int)’: user.cpp:53:19: warning: ‘current’ may be used uninitialized in this function [-Wmaybe-uninitialized] sum += current; ^