版权声明:本文为博主原创文章,转载请注明出处。 https://blog.csdn.net/yuankundong/article/details/53069287
public class SumDemo {
//1到100相加
public static void main(String[] args) {
System.out.println("方法1:"+sum1());
System.out.println("方法2:"+sum2());
System.out.println("方法3:"+sum3(100));
}
<span class="hljs-comment">//方法1 while循环</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum1</span>(){
<span class="hljs-keyword">int</span> sum = <span class="hljs-number">0</span>;
<span class="hljs-keyword">int</span> i = <span class="hljs-number">0</span>;
<span class="hljs-keyword">while</span>(i<=<span class="hljs-number">100</span>){
sum+=i;
i++;
}
<span class="hljs-keyword">return</span> sum;
}
<span class="hljs-comment">//方法2 for循环</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum2</span>(){
<span class="hljs-keyword">int</span> sum = <span class="hljs-number">0</span>;
<span class="hljs-keyword">for</span>(<span class="hljs-keyword">int</span> i=<span class="hljs-number">0</span>;i<=<span class="hljs-number">100</span>;i++){
sum+=i;
}
<span class="hljs-keyword">return</span> sum;
}
<span class="hljs-comment">//方法3 递归</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum3</span>(<span class="hljs-keyword">int</span> num){
<span class="hljs-keyword">if</span>(num==<span class="hljs-number">1</span>){
<span class="hljs-keyword">return</span> <span class="hljs-number">1</span>;
}
<span class="hljs-keyword">else</span>{
<span class="hljs-keyword">return</span> num+sum3(num-<span class="hljs-number">1</span>);
}
}
}
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输出结果:
方法1:5050
方法2:5050
方法3:5050
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</div>
版权声明:本文为博主原创文章,转载请注明出处。 https://blog.csdn.net/yuankundong/article/details/53069287
public class SumDemo {
//1到100相加
public static void main(String[] args) {
System.out.println("方法1:"+sum1());
System.out.println("方法2:"+sum2());
System.out.println("方法3:"+sum3(100));
}
<span class="hljs-comment">//方法1 while循环</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum1</span>(){
<span class="hljs-keyword">int</span> sum = <span class="hljs-number">0</span>;
<span class="hljs-keyword">int</span> i = <span class="hljs-number">0</span>;
<span class="hljs-keyword">while</span>(i<=<span class="hljs-number">100</span>){
sum+=i;
i++;
}
<span class="hljs-keyword">return</span> sum;
}
<span class="hljs-comment">//方法2 for循环</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum2</span>(){
<span class="hljs-keyword">int</span> sum = <span class="hljs-number">0</span>;
<span class="hljs-keyword">for</span>(<span class="hljs-keyword">int</span> i=<span class="hljs-number">0</span>;i<=<span class="hljs-number">100</span>;i++){
sum+=i;
}
<span class="hljs-keyword">return</span> sum;
}
<span class="hljs-comment">//方法3 递归</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">int</span> <span class="hljs-title">sum3</span>(<span class="hljs-keyword">int</span> num){
<span class="hljs-keyword">if</span>(num==<span class="hljs-number">1</span>){
<span class="hljs-keyword">return</span> <span class="hljs-number">1</span>;
}
<span class="hljs-keyword">else</span>{
<span class="hljs-keyword">return</span> num+sum3(num-<span class="hljs-number">1</span>);
}
}