关键字是在C++库中预定义或保留的单词，具有固定的含义，并用于执行内部操作。C++语言支持超过64个关键字。

每个关键字都以小写字母形式存在，如auto、break、case、const、continue、int等。

C++语言中的32个关键字也可在C语言中使用。

这是C++中新增的30个保留字，不在C语言中。

Input: str=”for”
Output: for is a keyword

Explanation

• 关键字是程序中不能用作变量名的保留字。

• C编程语言中有32个关键字。

将字符串与每个关键字进行比较，如果字符串相同，则字符串是关键字。

Example

示例

#include <stdio.h>
#include <string.h>
int main() {
   char keyword[32][10]={
      "auto","double","int","struct","break","else","long",
      "switch","case","enum","register","typedef","char",
      "extern","return","union","const","float","short",
      "unsigned","continue","for","signed","void","default",
      "goto","sizeof","voltile","do","if","static","while"
   } ;
   char str[]="which";
   int flag=0,i;
   for(i = 0; i < 32; i++) {
      if(strcmp(str,keyword[i])==0) {
         flag=1;
      }
   }
   if(flag==1)
      printf("%s is a keyword",str);
   else
      printf("%s is not a keyword",str);
}

输出

which is a keyword