Language: C++

#include<iostream>
#include<string>
using namespace std;
int main(void){
????????int a[10];
????????string n;
??????????
????????while(cin>>n){
????????????????for(int i = 0; i < 10 ; i ++ )a[i]=n[i]-'0';
????????????????for(int i = 9; 0 < i; i --)
????????????????????????for(int j = 0 ; j <= i ; j ++)
????????????????????????????????a[j] =(a[j] + a[j+1])%10;
????????????????cout<<a[0]<<endl;
????????}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:1: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      | ^
a.cc:5:2: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |  ^
a.cc:5:3: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |   ^
a.cc:5:4: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |    ^
a.cc:5:5: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |     ^
a.cc:5:6: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |      ^
a.cc:5:7: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |       ^
a.cc:5:8: error: expected primary-expression before '?' token
    5 | ????????int a[10];
      |        ^
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:5:9: error: expected ':' before 'int'
    5 | ????????int a[10];
      |         ^~~
      |         :
a.cc:5:9: error: expected primary-expression before 'int'
    5 | ????????int a[10];
      |         ^~~
a.cc:6:1: error: expected primary-expression before '?' token
    6 | ????????string n;
      | ^
a.cc:6:2: error: expected primary-expression before '?' token
    6 | ????????string n;
      |  ^
a.cc:6:3: error: expected primary-expression before '?' token
    6 | ????????string n;
      |   ^
a.cc:6:4: error: expected primary-expression before '?' token
    6 | ????????string n;
      |    ^
a.cc:6:5: error: expected primary-expression before '?' token
    6 | ????????string n;
      |     ^
a.cc:6:6: error: expected primary-expression before '?' token
    6 | ????????string n;
      |      ^
a.cc:6:7: error: expected primary-expression before '?' token
    6 | ????????string n;
      |       ^
a.cc:6:8: error: expected primary-expression before '?' token
    6 | ????????string n;
      |        ^
a.cc:6:16: error: expected primary-expression before 'n'
    6 | ????????string n;
      |                ^
a.cc:6:15: error: expected ':' before 'n'
    6 | ????????string n;
      |               ^~
      |               :
a.cc:6:16: error: 'n' was not declared in this scope
    6 | ????????string n;
      |                ^
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:6:17: error: expected ':' before ';' token
    6 | ????????string n;
      |                 ^
      |                 :
a.cc:6:17: error: expected primary-expression before ';' token
a.cc:7:1: error: expected primary-expression before '?' token
    7 | ??????????
      | ^
a.cc:7:2: error: expected primary-expression before '?' token
    7 | ??????????
      |  ^
a.cc:7:3: error: expected primary-expression before '?' token
    7 | ??????????
      |   ^
a.cc:7:4: error: expected primary-expression before '?' token
    7 | ??????????
      |    ^
a.cc:7:5: error: expected primary-expression before '?' token
    7 | ??????????
      |     ^
a.cc:7:6: error: expected primary-expression before '?' token
    7 | ??????????
      |      ^
a.cc:7:7: error: expected primary-expression before '?' token
    7 | ??????????
      |       ^
a.cc:7:8: error: expected primary-expression before '?' token
    7 | ??????????
      |        ^
a.cc:7:9: error: expected primary-expression before '?' token
    7 | ??????????
      |         ^
a.cc:7:10: error: expected primary-expression before '?' token
    7 | ??????????
      |          ^
a.cc:8:1: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      | ^
a.cc:8:2: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |  ^
a.cc:8:3: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |   ^
a.cc:8:4: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |    ^
a.cc:8:5: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |     ^
a.cc:8:6: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |      ^
a.cc:8:7: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |       ^
a.cc:8:8: error: expected primary-expression before '?' token
    8 | ????????while(cin>>n){
      |        ^
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
a.cc:8:9: error: expected ':' before 'while'
    8 | ????????while(cin>>n){
      |         ^~~~~
      |         :
a.cc:8:9: error: expected primary-expression before 'while'
    8 | ????????while(cin>>n){
      |