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- #include <stdbool.h>
- #include <stdio.h>
- #include <string.h>
- #include <stdlib.h>
- // Returns 'true' if the character is a DELIMITER.
- bool isDelimiter(char ch)
- {
- if (ch == ' ' || ch == '+' || ch == '-' || ch == '*' ||
- ch == '/' || ch == ',' || ch == ';' || ch == '>' ||
- ch == '<' || ch == '=' || ch == '(' || ch == ')' ||
- ch == '[' || ch == ']' || ch == '{' || ch == '}')
- return (true);
- return (false);
- }
- // Returns 'true' if the character is an OPERATOR.
- bool isOperator(char ch)
- {
- if (ch == '+' || ch == '-' || ch == '*' ||
- ch == '/' || ch == '>' || ch == '<' ||
- ch == '=')
- return (true);
- return (false);
- }
- // Returns 'true' if the string is a VALID IDENTIFIER.
- bool validIdentifier(char* str)
- {
- if (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]) == true)
- return (false);
- return (true);
- }
- // Returns 'true' if the string is a KEYWORD.
- bool isKeyword(char* str)
- {
- if (!strcmp(str, "if") || !strcmp(str, "else") ||
- !strcmp(str, "while") || !strcmp(str, "do") ||
- !strcmp(str, "break") ||
- !strcmp(str, "continue") || !strcmp(str, "int")
- || !strcmp(str, "double") || !strcmp(str, "float")
- || !strcmp(str, "return") || !strcmp(str, "char")
- || !strcmp(str, "case") || !strcmp(str, "char")
- || !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"))
- return (true);
- return (false);
- }
- // Returns 'true' if the string is an INTEGER.
- bool isInteger(char* str)
- {
- int i, len = strlen(str);
- if (len == 0)
- return (false);
- for (i = 0; i < len; i++) {
- if (str[i] != '0' && str[i] != '1' && str[i] != '2'
- && str[i] != '3' && str[i] != '4' && str[i] != '5'
- && str[i] != '6' && str[i] != '7' && str[i] != '8'
- && str[i] != '9' || (str[i] == '-' && i > 0))
- return (false);
- }
- return (true);
- }
- // Returns 'true' if the string is a REAL NUMBER.
- bool isRealNumber(char* str)
- {
- int i, len = strlen(str);
- bool hasDecimal = false;
- if (len == 0)
- return (false);
- for (i = 0; i < len; i++) {
- if (str[i] != '0' && str[i] != '1' && str[i] != '2'
- && str[i] != '3' && str[i] != '4' && str[i] != '5'
- && str[i] != '6' && str[i] != '7' && str[i] != '8'
- && str[i] != '9' && str[i] != '.' ||
- (str[i] == '-' && i > 0))
- return (false);
- if (str[i] == '.')
- hasDecimal = true;
- }
- return (hasDecimal);
- }
- // Extracts the SUBSTRING.
- char* subString(char* str, int left, int right)
- {
- int i;
- char* subStr = (char*)malloc(
- sizeof(char) * (right - left + 2));
- for (i = left; i <= right; i++)
- subStr[i - left] = str[i];
- subStr[right - left + 1] = '\0';
- return (subStr);
- }
- void parse(char* str)
- {
- int left = 0, right = 0;
- int len = strlen(str);
- while (right <= len && left <= right) {
- if (isDelimiter(str[right]) == false)
- right++;
- if (isDelimiter(str[right]) == true && left == right) {
- if (isOperator(str[right]) == true)
- printf("'%c' IS AN OPERATOR\n", str[right]);
- right++;
- left = right;
- } else if (isDelimiter(str[right]) == true && left != right
- || (right == len && left != right)) {
- char* subStr = subString(str, left, right - 1);
- if (isKeyword(subStr) == true)
- printf("'%s' IS A KEYWORD\n\n", subStr);
- else if (isInteger(subStr) == true)
- printf("'%s' IS AN INTEGER\n", subStr);
- else if (isRealNumber(subStr) == true)
- printf("'%s' IS A REAL NUMBER\n", subStr);
- else if (validIdentifier(subStr) == true
- && isDelimiter(str[right - 1]) == false){
- printf("'%s' IS A VALID IDENTIFIER\n", subStr);
- if(strcmp(subStr, "a")==0)
- {
- }
- else if (strcmp(subStr, "b")==0)
- {
- int v1 = 10;
- int v2 = 15;
- int c = v1+v2;
- if(c>10)
- {
- printf("Yes\n");
- }
- else{
- printf("Yes\n");
- }
- }
- }
- else if (validIdentifier(subStr) == false
- && isDelimiter(str[right - 1]) == false)
- printf("'%s' IS NOT A VALID IDENTIFIER\n", subStr);
- left = right;
- }
- }
- return;
- }
- int main()
- {
- char str[100] = "int a = 8; float b = 2.5; float c = a+b";
- parse(str);
- return (0);
- }
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