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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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