[C++知识库]“21天好习惯”第一期-2

C语言中使用%c输入数据时的一些问题，在用%c格式符读入字符时，空格字符和转义字符都会作为有效字符输入，

#include <stdio.h>
int main()
{
    int a;
    char b;
    float c;
    printf("Please input a integer:");
    scanf("%d",&a);
    printf("integer:%d\n",a);
    printf("Please input a character:");
    scanf("%c",&b);
    printf("character:%c\n",b);
    printf("Please input a float number:");
    scanf("%f",&c);
    printf("float:%f\n",c);
    return 0;
}

此时用%c输出的字符就会出现错误，

Please input a integer:10
integer:10
Please input a character:character:

Please input a float number:1.25
float:1.250000

Process returned 0 (0x0) ? execution time : 7.018 s
Press any key to continue.
而我们可以通过加入空格和getchar()函数来解决。

#include <stdio.h>
int main()
{
    int a;
    char b;
    float c;
    printf("Please input a integer:");
    scanf("%d",&a);
    printf("integer:%d\n",a);
    printf("Please input a character:");
    scanf(" %c",&b);
    printf("character:%c\n",b);
    printf("Please input a float number:");
    scanf("%f",&c);
    printf("float:%f\n",c);
    return 0;
}

Please input a integer:10
integer:10
Please input a character:a
character:a
Please input a float number:1.25
float:1.250000

Process returned 0 (0x0) ? execution time : 6.695 s
Press any key to continue.
?

#include <stdio.h>
int main()
{
    int a;
    char b;
    float c;
    printf("Please input a integer:");
    scanf("%d",&a);
    printf("integer:%d\n",a);
    printf("Please input a character:");
    getchar();
    scanf("%c",&b);
    printf("character:%c\n",b);
    printf("Please input a float number:");
    scanf("%f",&c);
    printf("float:%f\n",c);
    return 0;
}

Please input a integer:10
integer:10
Please input a character:a
character:a
Please input a float number:1.25
float:1.250000

Process returned 0 (0x0) ? execution time : 5.889 s
Press any key to continue.
?

这样，问题就解决了。