How to correctly use the ternary operator

Question

Given the the below two statements, could someone help me use only the ternary operator instead of if statements?

I have tried a lot to do that:

if(strstr(cv[i],a.c_str()))
{
    o=1;
    p=cv[i];
    p=p.substr(a.size()+1);
}
else o+=4;

if (b^*s && c++ + 1 ^ *s)
{
    cout << b;
    if (b^--c)
        cout << (c - b>1 ? "-" : ",") << c;

    if (a)
        cout << ",";
    b = c = *s;
}

Answer 1

The ternary operator is an expression, which returns a value when evaluated:

<result> = <condition> ? <when true> : <when false>

In this pseudo code <when true> and <when false> must also be an expression. Although you can pack several statements into a single expression with some trick (e.g. to embrace it with a do { <statements> } while(false); structure), the ternary operator is not meant to be used for this. You should use a ternary operator when both the then and the else branches are consisted of a single statement, and optionally you may use the return value of the expression.

So to take a very simple example, instead of writing

if(x > 0)
  y += 10;
else
  y += 20;

It is cleaner and simpler to use a ternary operator:

y += x > 0 ? 10 : 20;

However it is not the case when the conditional branches contain multiple statements, as in that case the use of a ternary operator would just make your code look more confusing and harder to understand.