关于C语言char函数的基本问题?

Question

#include "stdio.h"

void main()

{
char c;
printf("please input a character:");
c=getchar(); 
if(c < 32)
{
printf("This is a control character\n");
}
else if("c >= '0' && c<='9'")
{
printf("This is an integer\n");
}
else if ("c>='a' && c<= 'z'")
{
printf("This is a small letter\n");
}
else if ("c>='A' && c<='Z'")
{
printf("This is a capital letter\n");
}
else
{
printf("This is another character\n");
}
}
这个程序我本来是想随便输一个符号就能帮我自动归类
但是不管输入什么都说这是一个整数
怎么回事?

Answer 1

#include "stdio.h"void main(){char c;printf("please input a character:");c=getchar();if(c < 32){printf("This is a control character\n");}else if((c >= '0') && (c<='9')){printf("This is an integer\n");}else if ((c>='a') && (c<= 'z')){printf("This is a small letter\n");}else if ((c>='A') && (c<='Z')){printf("This is a capital letter\n");}else{printf("This is another character\n");}}

Answer 2

if("c >= '0' && c<='9'")这里的双引号是干什么的？应该是if(c >= '0' && c<='9')