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  1. #include <stdio.h>
  2. #include <string.h>
  3. #include <ctype.h>
  4.  
  5. void tokenize(const char *input)
  6. {
  7.     int i = 0;
  8.     int len = strlen(input);
  9.  
  10.     printf("\nTokens Found:\n");
  11.  
  12.     while (i < len)
  13.     {
  14.         // Skip whitespace
  15.         if (isspace(input[i]))
  16.         {
  17.             i++;
  18.             continue;
  19.         }
  20.  
  21.         // Check for two-character operators
  22.         if (i + 1 < len)
  23.         {
  24.             char two[3] = {input[i], input[i + 1], '\0'};
  25.  
  26.             if (strcmp(two, "+=") == 0 || strcmp(two, "-=") == 0 ||
  27.                 strcmp(two, "*=") == 0 || strcmp(two, "/=") == 0 ||
  28.                 strcmp(two, ">=") == 0 || strcmp(two, "<=") == 0 ||
  29.                 strcmp(two, "==") == 0 || strcmp(two, "!=") == 0)
  30.             {
  31.  
  32.                 printf("OPERATOR: %s\n", two);
  33.                 i += 2;
  34.                 continue;
  35.             }
  36.         }
  37.  
  38.         // Single-character operators
  39.         if (input[i] == '+' || input[i] == '-' || input[i] == '*' ||
  40.             input[i] == '/' || input[i] == '=' || input[i] == '>' ||
  41.             input[i] == '<' || input[i] == '!')
  42.         {
  43.  
  44.             printf("OPERATOR: %c\n", input[i]);
  45.             i++;
  46.             continue;
  47.         }
  48.  
  49.         // Identifiers / keywords
  50.         if (isalpha(input[i]) || input[i] == '_')
  51.         {
  52.             char buffer[256];
  53.             int j = 0;
  54.             while (i < len && (isalnum(input[i]) || input[i] == '_'))
  55.             {
  56.                 buffer[j++] = input[i++];
  57.             }
  58.             buffer[j] = '\0';
  59.             printf("IDENTIFIER: %s\n", buffer);
  60.             continue;
  61.         }
  62.  
  63.         // Numbers
  64.         if (isdigit(input[i]))
  65.         {
  66.             char buffer[256];
  67.             int j = 0;
  68.             while (i < len && isdigit(input[i]))
  69.             {
  70.                 buffer[j++] = input[i++];
  71.             }
  72.             buffer[j] = '\0';
  73.             printf("NUMBER: %s\n", buffer);
  74.             continue;
  75.         }
  76.  
  77.         // Unknown character
  78.         printf("UNKNOWN: %c\n", input[i]);
  79.         i++;
  80.     }
  81. }
  82.  
  83. int main()
  84. {
  85.     char input[1024];
  86.     printf("Enter a simple C code snippet: ");
  87.     fgets(input, sizeof(input), stdin);
  88.  
  89.     // Remove trailing newline
  90.     input[strcspn(input, "\n")] = '\0';
  91.  
  92.     tokenize(input);
  93.     return 0;
  94. }
Success #stdin #stdout 0.01s 5304KB
comments (?)
stdin
copy 
== +=
stdout
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Enter a simple C code snippet: 
Tokens Found:
OPERATOR: ==
OPERATOR: +=
https://ideone.com/Qux2QF
language:
C (gcc 8.3)
created:
21 hours ago
visibility:
public

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