View Compilation Error

0_0_24476820_31751.cpp: In function 'int main()':
0_0_24476820_31751.cpp:22:13: error: cannot convert 'int*' to 'char*' for argument '1' to 'char* gets(char*)'
   gets(pre_a);
             ^
0_0_24476820_31751.cpp:24:16: error: cannot convert 'int*' to 'char*' for argument '1' to 'char* gets(char*)'
   gets(middle_b);
                ^
0_0_24476820_31751.cpp:34:24: error: cannot convert 'int*' to 'char*' for argument '1' to 'void func(char*, char*, int)'
   func(middle, pre, len);
                        ^