使用printf和scanf写入c不能按预期工作

Question

所以我是C的新手。我正在使用带有MinGW编译器的eclipse。我在第二章使用scanf和printf函数，我的程序正在运行，但只有在我将三个整数输入scanf函数后才将语句打印到控制台。

#include <stdio.h>
int main(void){
    int length, height, width, volume, dweight;

    printf("Enter the box length: ");
    scanf("%d", &length);
    printf("\nEnter the box width: ");
    scanf("%d", &width);
    printf("\nEnter the box height");
    scanf("%d", &height);

    volume = length * width * height;
    dweight = (volume + 165) / 166;

    printf("Dimensions: l = %d, w = %d, h = %d\n", length, width, height);
    printf("Volume: %d\n", volume);
    printf("Dimensional Width: %d\n", dweight);

    return 0;
}

控制台输出：

8 (user input + "Enter" + key)
10 (user input + "Enter" key)
12 (user input + "Enter" key)
Enter the box length: 
Enter the box width: 
Enter the box heightDimensions: l = 8, w = 10, h = 12
Volume: 960
Dimensional Width: 6

任何见解？我期待它到printf，然后scanf用户输入如下：

Enter the box length: (waits for user int input; ex. 8 + "Enter")
Enter the box width: ...

Answer 1

在致电fflush(stdout);之前，只需在每个printf()后添加scanf()：

#include <stdio.h>
int main(void){
    int length, height, width, volume, dweight;

    printf("Enter the box length: "); fflush(stdout);
    scanf("%d", &length);
    printf("\nEnter the box width: "); fflush(stdout);
    scanf("%d", &width);
    printf("\nEnter the box height"); fflush(stdout);
    scanf("%d", &height);

    volume = length * width * height;
    dweight = (volume + 165) / 166;

    printf("Dimensions: l = %d, w = %d, h = %d\n", length, width, height);
    printf("Volume: %d\n", volume);
    printf("Dimensional Width: %d\n", dweight);

    return 0;
}

Answer 2

处理C中的Dirty Buffers !!

您可以在每个printf（）的末尾添加换行符（转义序列）＆＃39; \ n＆＃39; ，这用于刷新缓冲区，最终启用缓冲区显示在输出终端上。（相同的功能是通过fflush（stdout）实现的，但是每次调用printf（）时都不需要写它，只需要包含一个字符＆＃39; \ n＆＃39; < / em>的）

注意：始终建议使用＆＃39; \ n＆＃39;字符作为引号内的最后一个元素＆＃34;＆＃34;对于printf（），因为除非使用了刷新机制，否则数据将保留在缓冲区内，但是当main（）函数结束时，缓冲区会自动刷新，而且，只有在刷新临时缓冲区时，数据才会到达目标。

我们的新代码应如下所示：

#include <stdio.h>
int main(void){
    int length, height, width, volume, dweight;
    printf("Enter the box length: \n");
    scanf("%d", &length);
    printf("\nEnter the box width: \n");
    scanf("%d", &width);
    printf("\nEnter the box height \n");
    scanf("%d", &height);
    volume = length * width * height;
    dweight = (volume + 165) / 166;
    printf("Dimensions: l = %d, w = %d, h = %d\n", length, width, height);
    printf("Volume: %d\n", volume);
    printf("Dimensional Width: %d\n", dweight);
    return 0;
}

控制台输出：

Enter the box length: 
8
Enter the box width:  
10
Enter the box height 
12
Dimensions: l = 8, w = 10, h = 12
Volume: 960
Dimensional Width: 6