foo.c:1:1: error: expected identifier or '(' before '~' token
 ~
 ^
foo.c:4:1: error: unknown type name 'string'
 string expr, name; VI I;
 ^
foo.c:4:20: error: unknown type name 'VI'
 string expr, name; VI I;
                    ^
foo.c: In function 'out':
foo.c:7:1: warning: implicit declaration of function 'SZ' [-Wimplicit-function-declaration]
 if (k == SZ(I)) cout << name; else{ printf("op(%d,",I[k]);out(k+1);printf(")"); } }
 ^
foo.c:7:17: error: 'cout' undeclared (first use in this function)
 if (k == SZ(I)) cout << name; else{ printf("op(%d,",I[k]);out(k+1);printf(")"); } }
                 ^
foo.c:7:17: note: each undeclared identifier is reported only once for each function it appears in
foo.c:7:1: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
 if (k == SZ(I)) cout << name; else{ printf("op(%d,",I[k]);out(k+1);printf(")"); } }
 ^
foo.c:7:37: warning: incompatible implicit declaration of built-in function 'printf' [enabled by default]
 if (k == SZ(I)) cout << name; else{ printf("op(%d,",I[k]);out(k+1);printf(")"); } }
                                     ^
foo.c:7:54: error: subscripted value is neither array nor pointer nor vector
 if (k == SZ(I)) cout << name; else{ printf("op(%d,",I[k]);out(k+1);printf(")"); } }
                                                      ^
foo.c: In function 'gao':
foo.c:11:1: warning: implicit declaration of function 'FOR' [-Wimplicit-function-declaration]
 if (k == SZ(I)){ FOR(i,l,r)putchar(expr[i]);puts(""); } else{
 ^
foo.c:11:22: error: 'i' undeclared (first use in this function)
 if (k == SZ(I)){ FOR(i,l,r)putchar(expr[i]);puts(""); } else{
                      ^
foo.c:11:28: error: expected ';' before 'putchar'
 if (k == SZ(I)){ FOR(i,l,r)putchar(expr[i]);puts(""); } else{
                            ^
foo.c:11:28: warning: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
foo.c:12:32: error: unknown type name 'VII'
     int c=0;char op='(';int ll;VII cut;
                                ^
foo.c:13:16: error: expected ';' before 'if'
     FOR(i,l,r) if(expr[i]=='('){if (!c++)ll=i+1;}
                ^
foo.c:12:36: warning: unused variable 'cut' [-Wunused-variable]
     int c=0;char op='(';int ll;VII cut;
                                    ^
foo.c:12:29: warning: unused variable 'll' [-Wunused-variable]
     int c=0;char op='(';int ll;VII cut;
                             ^
foo.c:12:18: warning: unused variable 'op' [-Wunused-variable]
     int c=0;char op='(';int ll;VII cut;
                  ^
foo.c:12:9: warning: unused variable 'c' [-Wunused-variable]
     int c=0;char op='(';int ll;VII cut;
         ^
foo.c: In function 'main':
foo.c:34:1: error: unknown type name 'ifndef'
 ifndef ONLINE_JUDGE
 ^
foo.c:36:1: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'freopen'
 freopen("in.txt", "r", stdin);
 ^
foo.c:38:1: error: 'endif' undeclared (first use in this function)
 endif
 ^
foo.c:40:1: error: expected ';' before 'while'
 while (cin >> expr){
 ^
foo.c: At top level:
foo.c:50:3: error: expected identifier or '(' before '~' token
 } ~
   ^
foo.c: In function 'main':
foo.c:50:1: warning: control reaches end of non-void function [-Wreturn-type]
 } ~
 ^