Why break cannot be used with ternary operator?

问题

while(*p!='\0' && *q!='\0')
{
        if(*p==*q)
        {
               p++;
               q++;
               c++;
        }
        else
        break;
}

I have written this using ternary operator but why its giving error for break statement?

*p==*q?p++,q++,c++:break;

gcc compiler gives this error: expected expression before ‘break’

回答1:

When you use a ternary operator, it is not like an if. The ternary operator has this form:

(condition ? expression_if_true : expression_if_false);

Those two expression must have the same type, otherwise that makes nonsense.

And as Thilo said, you cannot use statement in this operator, only expression. This is because the whole ternary operator must be an expression itself, depending on the condition.

回答2:

The syntax is:

(condition ? expr_true : expr_false);

expr_true and expr_false must have a common type (which will be the result of the ternary operator). Also, of course, break is not an expression, it is a statement.

来源：https://stackoverflow.com/questions/37855337/why-break-cannot-be-used-with-ternary-operator