View Compilation Error

0_0_21909680_6790.cpp: In function 'int main()':
0_0_21909680_6790.cpp:2:33: error: 'a' was not declared in this scope
 int main(){while(~scanf("%d%d",&a,&b))printf("%d\n",a+b);}
                                 ^
0_0_21909680_6790.cpp:2:36: error: 'b' was not declared in this scope
 int main(){while(~scanf("%d%d",&a,&b))printf("%d\n",a+b);}
                                    ^