[英]Converting for loop to do while loop in C++
I need to convert this for loop to a do while: 我需要将此for循环转换为do:
for (int i = 0; i <= input; i = i + 2)
{
cout << name << " is number " << input << endl;
total = total + i;
}
cout << endl;
cout << total << endl;
This is what I have so far: 这是我到目前为止的内容:
do
{
cout << name << " is number " << input << endl;
i += 2;
total += i;
} while (i <= input);
cout << endl;
cout << total << endl;
It doesn't give the same total value as the for loop. 它的总价值与for循环的价值不同。 What am I doing wrong?
我究竟做错了什么?
You have to add i to the total before incrementing it by 2 您必须将i加到总数上,然后再加2
So the do..while loop should be like this: 所以do..while循环应该像这样:
do
{
cout << name << " is number " << input << endl;
total += i;
i += 2;
} while (i <= input);
cout << endl;
cout << total << endl;
The main difference between for loop and do-while loop is the fact that: for循环和do-while循环之间的主要区别在于以下事实:
Example: 例:
int input = 100;
//Will never execute as i is bigger than 5
for (int i = input; i<5; ++i)
cout << i;
//Will execute only one time as i < 5 is checked only
//after first execution
int i = input;
do
{
cout << i;
} while(i < 5);
The way to correctly do you task is: 正确执行任务的方法是:
int i = 0;
//if used to prevent first execution
if (i <= input)
{
do
{
cout << name << " is number " << input << endl;
total = total + i;
i = i + 2;
} while(i <= input);
}
But for is better to rewrite for loop like 但是for最好重写for循环,例如
for(BEFORE_STATEMENT; FINISH_STATEMENT; ITERATE_STATEMENT)
{
LOOP_CODE
}
as while loop, which will work the same 就像while循环一样
BEFORE_STATEMENT
while(FINISH_STATEMENT)
{
LOOP_CODE
ITERATE_STATEMENT
}
You just need to change 你只需要改变
i += 2;
total += i;
to 至
total += i;
i += 2;
In your for loop: 在您的for循环中:
total = total + i;
i
is equal to 0 at the first iteration. 在第一次迭代时,
i
等于0。 The way you were doing it in the do - while
loop, i
was set to 2 before the total addition. 在
do - while
循环中执行do - while
的方式,在总加法之前将i
设置为2。
If you haven't done so in a previous portion of the code, you need to initialize i in the do...while. 如果您在代码的上一部分中没有这样做,则需要在do ... while中初始化i。
Also, in the do...while, change the order to have total incremented before i is incremented. 另外,在做...的同时,更改顺序以使总数在i递增之前递增。
Your code is incorrect. 您的代码不正确。 Corect is
正确是
do
{
cout << name << " is number " << input << endl;
total += i;//swap these lines
i += 2;//
} while (i <= input);
cout << endl;
cout << total << endl;
a do while will be exectued at least one time, no mather what the value is i is. 一会儿将执行至少一次,但我不知道我的值是多少。 Also you should initialise your i.
你也应该初始化你的i。
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