eclipse中的关于scanf和printf的输入顺序的解决办法

最新推荐文章于 2023-02-27 21:29:58 发布

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本文介绍了解决Eclipse环境中使用C语言编程时遇到的scanf和printf输入输出顺序问题。通过在scanf前使用fflush(stdout)来刷新输出缓冲区，可以确保程序按预期顺序接收用户输入。

eclipse中的关于scanf和printf的输入顺序的解决办法

The eclipse console has weird behaviour when used for input with C programs.

I teach C to first year undergraduates and I want them to learn their way through eclipse. But the small silly programs that ask you to input characters have weird behaviour, if you use the eclipse console. It seems like it groups all input and output commands and executes them together...for example...

the following program:

#include <stdio.h>

int main() {
int n = 0;
printf("Gimme a number: ");
scanf ("%d", &n);
printf("/nThe number you entered was %d/n", n);

return 0;
}

has the following output:

4
Gimme a number: The number you entered was 4

Pretty normal output on any console you'll find, not just with eclipse's one

instead of：

Gimme a number: 4
The number you entered was 4

To obtain this output, you have to flush stdout before scanf'ing the number. The output is flushed either implicitely when a newline character is echoed on the console (printf("/n")) or explicitely with fflush(stdout);

to get the output you wanted use this program :

#include <stdio.h>

int main() {

int n = 0;
    printf("Gimme a number: ");
    fflush(stdout);
    scanf ("%d", &n);
    printf("/nThe number you entered was %d/n", n);

return 0;
}