C program to check if a given string is Keyword or not

Last Updated : 06 Feb, 2019

Given a string, the task is to write a program that checks if the given string is a keyword or not.

Keywords are reserved words which cannot be used as variable names.
There are 32 keywords in C programming language.

Examples:

Input: str = "geeks"
Output: geeks is not a keyword

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

// C program to check whether a given 
// string is a keyword or not 
#include <stdbool.h> 
#include <stdio.h> 
#include <string.h> 
  
// Function to check whether the given 
// string is a keyword or not 
// Returns 'true' if the string is a KEYWORD. 
bool isKeyword(char* str) 
{ 
    if (!strcmp(str, "auto") || !strcmp(str, "default")  
        || !strcmp(str, "signed") || !strcmp(str, "enum")  
        ||!strcmp(str, "extern") || !strcmp(str, "for")  
        || !strcmp(str, "register") || !strcmp(str, "if")  
        || !strcmp(str, "else")  || !strcmp(str, "int") 
        || !strcmp(str, "while") || !strcmp(str, "do") 
        || !strcmp(str, "break") || !strcmp(str, "continue")  
        || !strcmp(str, "double") || !strcmp(str, "float") 
        || !strcmp(str, "return") || !strcmp(str, "char") 
        || !strcmp(str, "case") || !strcmp(str, "const") 
        || !strcmp(str, "sizeof") || !strcmp(str, "long") 
        || !strcmp(str, "short") || !strcmp(str, "typedef") 
        || !strcmp(str, "switch") || !strcmp(str, "unsigned") 
        || !strcmp(str, "void") || !strcmp(str, "static") 
        || !strcmp(str, "struct") || !strcmp(str, "goto") 
        || !strcmp(str, "union") || !strcmp(str, "volatile")) 
        return (true); 
    return (false); 
} 
  
// Driver code 
int main() 
{ 
    isKeyword("geeks") ? printf("Yes\n") 
                       : printf("No\n"); 
    isKeyword("for") ? printf("Yes\n") 
                     : printf("No\n"); 
    return 0; 
} 

Output:

No
Yes

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