View Compilation Error

0_0_15320839_30642.cpp: In function 'int main()':
0_0_15320839_30642.cpp:6:5: error: expected initializer before 'op'
     op='1';
     ^
0_0_15320839_30642.cpp:8:22: error: 'op' was not declared in this scope
     while(scanf("%c",op)) 
                      ^