控制语句结构

if (x == 100)
cout << "x is 100";

if (x == 100)
{
cout << "x is ";
cout << x;
}

if (x == 100)
cout << "x is 100";elsecout << "x is not 100";

if (x > 0)
cout << "x is positive";
else if (x < 0)
cout << "x is negative";
else
cout << "x is 0";

while (n>0) {
cout << n << ", ";
--n;
}

do {
cout << "Enter number (0 to end): ";
cin >> n;
cout << "You entered: " << n << "\n";
} while (n != 0);

for (int n=10; n>0; n--) {
cout << n << ", ";
}

for ( n=0, i=100 ; n!=i ; n++, i-- )
{
// whatever here...
}

for (n=10; n>0; n--)
{
cout << n << ", ";
if (n==3)
{
cout << "countdown aborted!";
break;
}
}

for (int n=10; n>0; n--) {
if (n==5) continue;
cout << n << ", ";
}

int main ()
{
int n=10;
loop:
cout << n << ", ";
n--;
if (n>0) goto loop;
cout << "FIRE!\n";
return 0;
}

switch (x) {
case 1:
cout << "x is 1";
break;
case 2:
cout << "x is 2";
break;
default:
cout << "value of x unknown";
}

switch (x) {
case 1:
case 2:
case 3:
cout << "x is 1, 2 or 3";
break;
default:
cout << "x is not 1, 2 nor 3";
}

int x = 10;

int y=0;

switch (x) {
case 10:

y=30;
default:
y+=20;
}

//y == 50