View Compilation Error

0_0_25668089_29096.cpp: In function 'int main()':
0_0_25668089_29096.cpp:23:27: error: cannot pass objects of non-trivially-copyable type 'std::string {aka class std::basic_string<char>}' through '...'
             scanf("%s",str);  
                           ^
0_0_25668089_29096.cpp:43:27: error: cannot pass objects of non-trivially-copyable type 'std::string {aka class std::basic_string<char>}' through '...'
             scanf("%s",str);  
                           ^