C语言中如何实现字符串拼接 C语言字符串连接函数性能对比

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* safe_concat(const char* str1, const char* str2) {
    size_t len1 = strlen(str1);
    size_t len2 = strlen(str2);
    char* result = (char*)malloc(len1 + len2 + 1); // +1 for null terminator
    if (result == NULL) {
        return NULL; // 内存分配失败
    }
    strcpy(result, str1);
    strcat(result, str2); // 仍然需要小心，但现在我们控制了内存
    return result;
}

int main() {
    char* str1 = "Hello, ";
    char* str2 = "world!";
    char* combined = safe_concat(str1, str2);
    if (combined != NULL) {
        printf("%s\n", combined);
        free(combined); // 释放内存
    } else {
        printf("内存分配失败!\n");
    }
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* efficient_concat(const char* str1, const char* str2) {
    size_t len1 = strlen(str1);
    size_t len2 = strlen(str2);
    char* result = (char*)malloc(len1 + len2 + 1);
    if (result == NULL) {
        return NULL;
    }
    memcpy(result, str1, len1);
    memcpy(result + len1, str2, len2);
    result[len1 + len2] = '\0';
    return result;
}

int main() {
    char* str1 = "Fast";
    char* str2 = "Concat";
    char* combined = efficient_concat(str1, str2);
    if (combined != NULL) {
        printf("%s\n", combined);
        free(combined);
    } else {
        printf("Memory allocation failed!\n");
    }
    return 0;
}