View Compilation Error

0_0_30338993_16114.cpp: In function 'int main()':
0_0_30338993_16114.cpp:11:19: error: 'a' was not declared in this scope
    scanf("%d %d",&a,&b);
                   ^
0_0_30338993_16114.cpp:11:22: error: 'b' was not declared in this scope
    scanf("%d %d",&a,&b);
                      ^