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誰能用三種循環(huán) 寫出計算五十以內(nèi)的偶數(shù)和？

Java

此生不變丶 2016-04-27 14:30:46

while ? do ? ?while ? ? ? ? ?for

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3 回答

已采納

蜂之谷

TA貢獻(xiàn)564條經(jīng)驗(yàn) 獲得超863個贊

//for
int?sum1?=?0;
for?(int?i?=?0;?i?<?50;?i++)?{
????if?(i?%?2?==?0)?{
????????sum1?+=?i;
????}
}
System.out.println(sum1);
//while
int?sum2?=?0;
int?j?=?0;
while?(j?<?50)?{
????if?(j?%?2?==?0)?{
????????sum2?+=?j;
????}
????j++;
}
System.out.println(sum2);
//do?while
int?sum3?=?0;
int?k?=?0;
do?{
???if?(k?%?2?==?0)?{
???????sum3?+=?k;
???}
???k++;
}?while?(k?<?50);
System.out.println(sum3);

2 反對回復(fù) 2016-04-27

此生不變丶

TA貢獻(xiàn)36條經(jīng)驗(yàn) 獲得超19個贊

public?class?Test{
	public?static?void?main(String[]?args){
		int?sum=0;//?50以內(nèi)的偶數(shù)和；
		int?num=2;//?50以內(nèi)的偶數(shù)；
		//while
		while(num<=50){
			sum+=num;
			num+=2;
		}
		System.out.println("五十以內(nèi)的偶數(shù)和為："+sum);
		//?do...while
		int?sum1=0;
		int?num1=2;
		do{
			sum1+=num1;
			num1+=2;
		}while(num1<=50);
		System.out.println("50以內(nèi)的偶數(shù)和為："+sum1);
		//?for
		int?sum2=0;
		int?num2=2;
		for(num2=2;num2<=50;num2+=2){
			sum2+=num2;	
		}
		System.out.println("for五十以內(nèi)的偶數(shù)和為："+sum2);
	}
}

1 反對回復(fù) 2016-04-27

guozhchun

TA貢獻(xiàn)103條經(jīng)驗(yàn) 獲得超76個贊

public?class?Test
{
	void?testWhile()
	{
		int?num?=?2;
		int?sum?=?0;
		while?(num?<=?50)
		{
			sum?+=?num;
			num?+=?2;
		}
		
		System.out.println("while:?"?+?sum);
	}
	
	void?testDoWhile()
	{
		int?num?=?2;
		int?sum?=?0;
		do
		{
			sum?+=?num;
			num?+=?2;
		}
		while?(num?<=?50);
		
		System.out.println("do?while:?"?+?sum);
	}
	
	void?testFor()
	{
		int?sum?=?0;
		for?(int?i?=?2;?i?<=?50;?i?+=?2)
			sum?+=?i;
		
		System.out.println("for:?"?+?sum);
	}
	
	public?static?void?main(String[]?args)
	{
		Test?test?=?new?Test();
		test.testWhile();
		test.testDoWhile();
		test.testFor();
	}
}

1 反對回復(fù) 2016-04-27