logic.cpp: In function 'int calc()': logic.cpp:73: warning: array subscript has type 'char' logic.cpp: In function 'int main()': logic.cpp:130: warning: array subscript has type 'char' logic.cpp:132: warning: array subscript has type 'char' logic.cpp:123: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result logic.cpp:124: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result logic.cpp:126: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result logic.cpp: In function 'int pr(char)': logic.cpp:33: warning: control reaches end of non-void function /tmp/ccPLBypZ.o: In function `main': logic.cpp:(.text+0x10cb): warning: the `gets' function is dangerous and should not be used.