Compilare: user.cpp: In function ‘void process(expression&)’: user.cpp:101:88: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(e.s[i] != '~') while(!stk.empty() && stk.top() != '(' && prior[stk.top()] >= prior[e.s[i]]) { ^ user.cpp:101:105: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(e.s[i] != '~') while(!stk.empty() && stk.top() != '(' && prior[stk.top()] >= prior[e.s[i]]) { ^ user.cpp: In function ‘bool are_same(expression&, expression&)’: user.cpp:115:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:116:10: warning: unused variable ‘found’ [-Wunused-variable] bool found, val1, val2; ^ user.cpp: In function ‘bool getVal(expression&, char)’: user.cpp:150:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] return gen & (1 << e.v_index[x]); ^ user.cpp: In function ‘bool eval(expression&)’: user.cpp:154:17: warning: unused variable ‘j’ [-Wunused-variable] int i, val, j; ^ user.cpp: In function ‘int main()’: user.cpp:37:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(inFile, "r", stdin); ^ user.cpp:38:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(outFile, "w", stdout); ^ user.cpp:47:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:52:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(e1.s); ^ user.cpp:56:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(e2.s); ^ user.cpp: In function ‘bool eval(expression&)’: user.cpp:206:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ /tmp/ccnzffuC.o: In function `main': user.cpp:(.text.startup+0xc0): warning: the `gets' function is dangerous and should not be used.