if expr1) statement 1 形式三: else if (expr2) statement2 else if (expr3) statements ◆执行过程 else statement 列:if( salary>1000) index. 4 else if (salary>800) index.3 else if (salary>600) index-=0. 2 else if (salary>400) index=0. 1 else index=O statemnt1 statemnt2 statemnt3statemntn形式三： if ( expr1 ) statement1 else if (expr2 ) statement2 else if (expr3 ) statement3 …... [ else statementn ] expr1 statemnt1 非0 =0 expr2 expr3 statemnt2 statemnt3 statemntn 非0 非0 =0 =0 ◆执行过程： 例：if (salary>1000) index=0.4; else if (salary>800) index=0.3; else if (salary>600) index=0.2; else if (salary>400) index=0.1; else index=0;