Function term

code_snippets/Chapter07/chapter.7.6.2.cpp:127–160

deal with *, /, and %

// deal with *, /, and %
double term()
{
    double left = primary();
    Token t = ts.get(); // get the next token from token stream

    while(true) {
        switch (t.kind) {
        case '*':
            left *= primary();
            t = ts.get();
            break;
        case '/':
            {    
                double d = primary();
                if (d == 0) error("divide by zero");
                left /= d; 
                t = ts.get();
                break;
            }
        case '%':
            {    
                int i1 = narrow_cast<int>(left);
                int i2 = narrow_cast<int>(term());
                if (i2 == 0) error("%: divide by zero");
                left = i1%i2; 
                t = ts.get();
                break;
            }
        default: 
            ts.putback(t);        // put t back into the token stream
            return left;
        }
    }
}

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