如何使用“For”进行打印 [英] How Can I Print With "For"

问题描述

所以最后结果不是我想要的，在第一个数字之后还有一个额外的+不应该在那里，我怎么能解决这个问题，请帮帮我



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So at the end the result is not what i want, there is an extra "+" after the first number which shouldnt be there, how can I solve this problem, please help me out

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#include <iostream>
using namespace std;
void main(){
	system("color b");
	int cont = 0, b;
	cout << "insert N; ";
	cin >> b;
	cout << "the sum is ";
	for (int a = 1; a <= b; a += 2){
		cont = a + cont;
		cout << " + " << a;
	}
	cout << " = " << cont << endl;
	system("pause");
}

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Insert; 10
The sum is + 1 + 3 + 5 + 7 + 9 = 25

推荐答案

查看@pwasser的评论。



检查行

See the comment from @pwasser.

Examine the line

cout << " + " << a;

注意额外的+是之前第一个数字不是之后



考虑如何在循环的第一次迭代中不打印+。



我再次推荐你来自pwasser的评论...

Note that the extra "+" is before the first number not after it

Consider how you might not print that "+" on the first iteration of the loop.

I refer you again to the comment from pwasser...

Quote：

尝试一下。逐步完成循环，看看发生了什么

Try a bit harder. Step through your loop and see what is happening

for (c = 2; c <= (a * 2); c += 2){
		cout << c;
		if (c < (a * 2)) cout << "+";
	}

最后，omfg我终于明白了它是如何工作的：P，谢谢

finally, omfg I finally understood how that works :P, thanks

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