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#include <ctype.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_LENGTH 100

bool isDelimiter(char chr)
{
    return (chr == ' ' || chr == '+' || chr == '-' || chr == '*' || chr == '/' || chr == ',' || chr == ';' || chr == '%' || chr == '>'
    || chr == '<' || chr == '=' || chr == '(' || chr == ')' || chr == '[' || chr == ']' || chr == '{' || chr == '}');
}

bool isOperator(char chr)
{
    return (chr == '+' || chr == '-' || chr == '*' || chr == '/' || chr == '>' || chr == '<' || chr == '=');
}

bool isValidIdentifier(char *str)
{
    return (str[0] != '0' && str[0] != '1' && str[0] != '2' &&
    str[0] != '3' && str[0] != '4' && str[0] != '5' && str[0] != '6' &&
    str[0] != '7' && str[0] != '8' && str[0] != '9' &&
    !isDelimiter(str[0]));
}

bool isKeyword(char *str)
{
    const char *keywords[] = {"auto", "break", "case", "char",
    "const", "continue", "default", "do",
    "double", "else", "enum", "extern",
    "float", "for", "goto", "if",
    "int", "long", "register", "return",
    "short", "signed", "sizeof", "static",
    "struct", "switch", "typedef", "union",
    "unsigned", "void", "volatile",
    "while"};
    for (int i = 0; i < sizeof(keywords) / sizeof(keywords[0]);
    i++)
    {
        if (strcmp(str, keywords[i]) == 0)
        {

            return true;
        }
    }
    return false;
}

bool isInteger(char *str)
{
    if (str == NULL || *str == '\0')
    {
        return false;
    }
    int i = 0;
    while (isdigit(str[i]))
    {
        i++;
    }
    return str[i] == '\0';
}

char *getSubstring(char *str, int start, int end)
{
    int length = strlen(str);
    int subLength = end - start + 1;
    char *subStr = (char *)malloc((subLength + 1) * sizeof(char)); strncpy(subStr, str + start, subLength);
    subStr[subLength] = '\0'; return subStr;
}

int lexicalAnalyzer(char *input)
{
    int left = 0, right = 0; int len = strlen(input);
    while (right <= len && left <= right)
    {
        if (!isDelimiter(input[right]))
        right++;
        if (isDelimiter(input[right]) && left == right)
        {



            input[right]);


        }
        if (isOperator(input[right])) printf("Token: Operator, Value: %c\n",
        
        right++;
        left = right;
        
        else if (isDelimiter(input[right]) && left != right || (right == len && left != right))
        {


            1);


            subStr);


            subStr);
            char *subStr = getSubstring(input, left, right -
            
            if (isKeyword(subStr))
            printf("Token: Keyword, Value: %s\n",
            
            else if (isInteger(subStr)) printf("Token: Integer, Value: %s\n",
            
            else if (isValidIdentifier(subStr) &&
            
            !isDelimiter(input[right - 1]))
            printf("Token: Identifier, Value: %s\n",
            subStr);
            else if (!isValidIdentifier(subStr) &&
            !isDelimiter(input[right - 1]))
            printf("Token: Unidentified, Value: %s\n",
            
            subStr);
            
    }
}

left = right;

return 0;
}

int main()
{
    char lex_input[MAX_LENGTH] = "int a = b + c"; printf("For Expression \"%s\":\n", lex_input); lexicalAnalyzer(lex_input);
    printf(" \n");

    char lex_input01[MAX_LENGTH] = "int x=ab+bc+30+switch+ 0y "; printf("For Expression \"%s\":\n", lex_input01); lexicalAnalyzer(lex_input01);
    return (0);
}
})))
        })
        }
    }
}
}
    }
    }
}
        }
    }
}
}
}
}
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