int|char|float|double|void|return|if|else|for|while|do|switch|case|default|break|continue|static|const|extern|unsigned|signed|long|short|sizeof|struct|union|enum|typedef|goto|auto|register|volatile|inline|restrict|_Bool|printf|scanf|fopen|fclose|fprintf|fscanf|fgets|fputs|malloc|free|calloc|realloc|exit|system|strcpy|strncpy|strcat|strcmp|strlen|strchr|memset|memcpy|perror|getchar|putchar|sprintf|sscanf|fseek|ftell|rewind|clearerr|atoi|atof|atol|rand|srand|qsort|getenv|sqrt|pow|sin|cos|tan|log|exp|fabs|floor|ceil|time|clock|difftime|strftime|isdigit|isalpha|isspace|isupper|islower|toupper|tolower|strrchr|strstr|strtok|memmove|memcmp|#include <stdio.h>|#include <stdlib.h>|#include <string.h>|#define MAX_SIZE 1024|#ifndef DEBUG|#endif|a == b|c != d|i < count|x >= y|a && b|x || y|!is_done|value++|count--|sum += 5|result *= 2|*ptr|node->next|&variable|sizeof(int)|(char*)ptr|/* block comment */|// line comment|x & 1|mask | 0x0F|a ^ b|~bits|val << 2|num >> 1|condition ? true_val : false_val|int main(void) { printf("Hello!\n"); return 0; }|for (int i = 0; i < 10; i++) { sum += i; }|int *ptr = malloc(sizeof(int));|if (ptr == NULL) { perror("malloc failed"); return 1; }|free(ptr);|ptr = NULL;|struct Node { int data; struct Node* next; };|struct Node* head = malloc(sizeof(struct Node));|head->data = 10;|head->next = NULL;|int value = 20;|int *p_value = &value;|FILE *fp = fopen("data.txt", "w");|if (fp == NULL) { return -1; }|fprintf(fp, "Log entry.\n");|fclose(fp);|char buffer[256];|while (fgets(buffer, sizeof(buffer), fp) != NULL) { /* process line */ }|int main(int argc, char *argv[])|if (argc < 2) { printf("Usage: %s <file>\n", argv[0]); }|int matrix[5][5];|matrix[i][j] = i + j;|do { count++; } while (x < y);|switch(key) { case 'q': exit(0); break; default: break; }|enum Status { OK, ERROR, PENDING };|enum Status current = OK;|void (*func_ptr)(int);|func_ptr = &my_function;|(*func_ptr)(42);|union Data { int i; float f; char c; };|union Data d; d.i = 100;