在for循环中的scanf [英] scanf in a for loop
问题描述
在Stephen G. Kochan的书中，Programming in C有一个程序与
如下：
for（i = 1; i< = numOfGrades; ++ i）{
printf（输入等级＃％i：，i）;
scanf（" i％"& grade）;
。 ..
}
scanf命令是否暂停循环，直到收到用户输入？
运行此程序时循环继续运行而不会暂停
用户输入。
这里发生了什么？有人可以帮帮我吗？
JoshO。
In Stephen G. Kochan''s book "Programming in C" there is a program with the
following:
for(i = 1; i <= numOfGrades; ++i) {
printf("Enter grade #%i: ", i);
scanf("i%", &grade);
...
}
Does the scanf command pause the loop until the user input is received?
When I run this program the loop keeps on going without pausing for the
user input.
What is going on here? Can anyone please help me?
JoshO.
推荐答案
是的，scanf应该导致for循环暂停并允许你
输入你的整数。
我看到的语法错误是
scanf（" i％"& grade）;
应为
scanf（"％i"& grade）;
Yes, the scanf should cause the for loop to pause and allow you to
enter your integer.
The syntax error that I see is that
scanf("i%", &grade);
should be
scanf("%i", &grade);
写了
wrote
for（i = 1; i< = numOfGrades; ++ i）{
printf（ 输入等级＃％i：，i）;
scanf（i％，& grade）;
...
}
scanf命令是否会暂停循环，直到收到用户输入？
当我运行此程序时，循环继续运行而不会暂停
用户输入。
什么在这里？有人可以帮帮我吗？
for(i = 1; i <= numOfGrades; ++i) {
printf("Enter grade #%i: ", i);
scanf("i%", &grade);
...
}
Does the scanf command pause the loop until the user input is received?
When I run this program the loop keeps on going without pausing for the
user input.
What is going on here? Can anyone please help me?
你好错了％i asi％。这意味着scanf（）正在查找字母说明符后面的
字母，后面是NUL，这是非法的b $ b。在你的系统上它只是忽略它并返回。
当调用scanf（）时你应该检查返回值，这会成功地给出
个字段转换，主要是为了防止坏用户输入b / b $ b，但也要发现这种错误。
Yoy''ve mistyped the "%i" as "i%". This means that scanf() is looking for the
letter I followed by the field specifier, followed by a NUL, which is
illegal. On your system it is simply ignoring it and returning.
When calling scanf() you should check the return value, which gives the
number of fields successfully converted, mainly to guard against bad user
input but also to catch this sort of error.
" ;" <>写道：
"" <> wrote:
在Stephen G. Kochan的书中，Programming in C有一个程序
，其中包含以下内容：
for（i = 1; i< = numOfGrades; ++ i）{
printf（" Enter grade＃％i） ："，i）;
scanf（" i％"& grade）;
...
scanf命令是否会暂停直到用户输入是
收到的循环？当我运行这个程序时，循环继续运行而不会暂停用户输入的
。
这里发生了什么？有谁可以帮帮我？
JoshO。
In Stephen G. Kochan''s book "Programming in C" there is a program with the following:
for(i = 1; i <= numOfGrades; ++i) {
printf("Enter grade #%i: ", i);
scanf("i%", &grade);
...
}
Does the scanf command pause the loop until the user input is received? When I run this program the loop keeps on going without pausing for the user input.
What is going on here? Can anyone please help me?
JoshO.
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