3.4 执行控制
true and false
所有的条件语句都使一个条件表达式的truth或falsehood来决定执行流程.
if-else
if(Boolean-expression)
statement
or
if(Boolean-expression)
statement
else
statement
Iteration
while(Boolean-expression)
statement
do
statement
while(Boolean-expression);
for(initialization; Boolean-expression; step)
statement
switch
switch(integral-selector) {
case integral-value1 : statement; break;
case integral-value2 : statement; break;
case integral-value3 : statement; break;
case integral-value4 : statement; break;
case integral-value5 : statement; break;
// �
default: statement;
}