C語言是一種廣泛應用于系統編程和嵌入式設備控制的編程語言。而在現代開發中，JSON（JavaScript對象表示法）作為數據交換格式也已經成為了主流。那么在C語言中，如何去拼接JSON數據呢？

#include#include#include#include#define BUFSIZE 256
/* 向buffer拼接key-value對 */
void add_kv(char *buffer, char *key, char *value) {
strcat(buffer, "\"");
strcat(buffer, key);
strcat(buffer, "\":\"");
strcat(buffer, value);
strcat(buffer, "\",");
}
/* 向buffer拼接數組 */
void add_arr(char *buffer, char *key, char **values, size_t len) {
strcat(buffer, "\"");
strcat(buffer, key);
strcat(buffer, "\":[");
for (size_t i = 0; i< len; i++) {
strcat(buffer, "\"");
strcat(buffer, values[i]);
strcat(buffer, "\"");
if (i + 1< len) {
strcat(buffer, ",");
}
}
strcat(buffer, "],");
}
/* 根據參數生成JSON字符串 */
char *generate_json(char *category, char *name, char *age, char *langs[], size_t lang_len) {
char *buffer = malloc(BUFSIZE);
strcpy(buffer, "{");
add_kv(buffer, "Category", category);
add_kv(buffer, "Name", name);
add_kv(buffer, "Age", age);
add_arr(buffer, "Languages", langs, lang_len);
strcat(buffer, "\"\":null}");  // 最后一個key-value pair要特殊處理
return buffer;
}
int main() {
char *langs[] = {"C", "Python", "JavaScript"};
size_t lang_len = 3;
char *json_str = generate_json("Person", "Tom", "20", langs, lang_len);
printf("%s\n", json_str);
free(json_str);
return 0;
}

以上代碼實現了一個簡單的JSON拼接函數。通過向buffer參數不斷拼接key-value對和數組，最后得到完整的JSON字符串。在生成完JSON字符串之后，我們可以將其發送到服務器或從文件中讀取并解析。