Main.cc: In function ‘void dfs(char*, int)’: Main.cc:28:13: error: declaration of ‘int a’ shadows a parameter int a; ^ Main.cc:32:32: error: invalid conversion from ‘int’ to ‘char*’ [-fpermissive] a = c(a, b[i].d); ^ Main.cc:11:9: note: initializing argument 1 of ‘int c(char*, char*)’ int c(char a[], char b[]) ^