Question

分别利用for语句、while语句以及do while语句编写一个求和程序（即sum=1+2+3+…+n）

要求用Java编程

Answer 1

#include<stdio.h>void main(){ int i,n; int sum=0; scanf("%d",&n); for(i=1;i<=n;i++) sum+=i; printf("%d",sum);} void main(){ int i=0,n; int sum=0; while(i<=n) { i++;sum+=n; }printf("%d",sum);}------------------ int i=0,sum=0; int n;scanf("%d",&n);do{ i++; sum+=i;}while(i<=n);printf("%d",sum);}

Answer 2

public class Calc {

public static void main(String[] args) {

int n=Integer.parseInt(args[0]);
int sum=0;

//for
for(int i=1;i<=n;i++){
sum+=i;
}
System.out.println(sum);

//while
int i=1;
sum=0;
while(i<=n){
sum+=i;
i++;
}
System.out.println(sum);
//do-while
i=1;
sum=0;
do{
sum+=i;
i++;
}while(i<=n);
System.out.println(sum);
}
} n的值在执行时动态传入，例如java Calc 100

Answer 3

int sum=0;for(int i=1;i<n;i++){sum+=i;}int i=1while(i<n){sum+=i;i++;}do{sum+=i;}while(i++<n);System.out.print(sum);

Answer 4

public static void main(String[] args) {
int n=100;
int sum=0;
for(int i=1;i<=n;i++){
sum+=i;
}
System.out.println(sum);
}----------------------------------------- public static void main(String[] args) {
int n = 100;
int sum = 0;
int i = 0;
while (i <= n) {
sum+=i++;
}
System.out.println(sum);
} --------------------------------- public static void main(String[] args) {
int n = 100;
int sum = 0;
int i = 0;
do {
sum += i++;
} while (i <= n);
System.out.println(sum);
}