how to convert character into operator

1int Compute(char c, int a, int b)
2{
3    switch (c) {  
4    case '+': return a+b;
5    case '-': return a-b;
6    case '*': return a*b;
7    case '/': return a/b;
8    default: throw std::runtime_error("No such operator");
9    }
10}
11