public class P376 { public static void main(String[] args) { int sum=0; //初始化总和 for (int i=1;i<=100;i++) { //原题可看作是:10-20+30-43...+970-98+99-100,即1*10-2*10+...-100*10 if (i%2==0) { //所以让i从1到100循环,遇到偶数则总和自减,遇到奇数则总和自加 sum-=i*10; } else { sum+=i*10; } } System.out.println("sum= "+ sum); }}
for example int sum = 0; for (int i=13, j=1; i<=1003; i+=10; j*=-1) { sum += (i*j); } System.out.println(sum);
public static void getNum() { int sun = 0; boolean open = true; for (int i = 13; i <= 1003; i += 10) { if (open) { if (i == 13) sun = i; else { sun = sun - i; open = false; } } else { sun = sun + i; open = true; } } System.out.println(sun); }
int sum = 0; for (int i=13, j=1; i<=1003; i+=10, j*=-1) { //上面这里写错了,是[,]不是[;] sum += (i*j); } System.out.println(sum); 结果是-500
public static void main(String[] args) { int j=0; for(int i=0;i<1004;i++){ if((""+i).endsWith("3")){ j+=i; } } System.out.println(j); }
int sum = 0;
for (int i=13, j=1; i<=1003; i+=10; j*=-1) {
sum += (i*j);
}
System.out.println(sum);
int sun = 0;
boolean open = true;
for (int i = 13; i <= 1003; i += 10) {
if (open) {
if (i == 13)
sun = i;
else {
sun = sun - i;
open = false;
}
} else {
sun = sun + i;
open = true;
}
}
System.out.println(sun);
}
for (int i=13, j=1; i<=1003; i+=10, j*=-1) { //上面这里写错了,是[,]不是[;]
sum += (i*j);
}
System.out.println(sum);
结果是-500
int j=0;
for(int i=0;i<1004;i++){
if((""+i).endsWith("3")){
j+=i;
}
}
System.out.println(j);
}
int j=1;
int count=0;
boolean flag=false;
for(int i=13;i<1004;i++){
if((""+i).endsWith("3")){
if(count%2==0){
flag=true;
}
if(count%2!=0){
flag=false;
}
if(flag){
j-=i;
count++;
}
else{
j+=i;
count++;
}
}
}
System.out.println(j);
}刚才分辨不出加减号 现在分辨出了 结果是501
嗯public static void main(String[] args) {
System.out.println(-500);
}
public static void main(String[] args){
int sum=0;
for(int i=1;i<=100;i++){
if(i%2==0){
sum-=i*10+3;
}
else{
sum+=i*10+3;
}
}
System.out.println("sum="+sum);
}
}