For clarity, I'm going to rename your conditions P and Q (as is the convention in propositional logic)
if( P || Q)
{
P && A();
Q && B();
}
else
{
C();
}
Edit:
adding more checks is rather easy:
if( P || Q || R || S)
{
P && A();
Q && B();
R && D();
S && E();
}
else
{
C();
}
Edit, after comment:
Well how about this.
int runC = 1;
P && (runC=0, A());
Q && (runC=0, B());
R && (runC=0, D());
S && (runC=0, E());
runC && C();