將一個字符數組連接到另一個字符數組的末尾（沒有內置函數）

Question

我已經堅持了幾個小時，我需要將一個字符串連接到另一個字符串的末尾，然后將結果存儲在第三個字符串中（不使用預建函數。我很難試圖將我的結果存儲到另一個字符串中,我能夠瞥見我想要的東西但是它導致無限循環並且似乎沒有效果.任何人都可以對此有所了解嗎？

#include <iostream>

using namespace std;

void Concat(char arr1[], char arr2[], char arr3[]);

int main(){

    char arr1[] = {"Hello how are you? \0 "};
    char arr2[] = { "The weather was cloudy today, so it rained. \0" };
    char arr3[] = { "Coffee is a great way to start the day. \0" };

    Concat(arr1, arr2, arr3);
}

void Concat(char arr1[], char arr2[], char arr3[]){

    while (arr1 != '\0' && arr2 != '\0') {

        // (This outputs what a want, haveing string 2 concat to the end of the firs string) 
        // However there is no way to save it to another array or stop the infinte loop.
        //cout << arr1 << arr2 << endl; 

        arr1 + arr2 = arr3; // syntax error

    }


} 

Answer 1

快速解決您的問題：

void Concat(const char* input1, const char* input2, char* output)
{
    int i = 0;
    do {

        output[i] = *input1;
        i++;
        input1++;
    } while (*input1 != '\0');
    do {

        output[i] = *input2;
        i++;
        input2++;
    } while (*input2 != '\0');
}

注意：我不檢查輸出緩沖區是否有足夠的內存等，希望你可以自己編輯。

Answer 2

你可能想嘗試這樣的事情：

#include <iostream>

void concat(const char *arr1, const char *arr2, char *arr3);

int main(){
    const char *arr1("abc");
    const char *arr2("def");
    char arr3[10];

    concat(arr1, arr2, arr3);
    std::cout << "arr3 is " << arr3 << std::endl;
}

void concat(const char *arr1, const char *arr2, char *arr3){

    if (arr1) {
        while(*arr1 != '\0') {
            *arr3 = *arr1;
            ++arr1; ++arr3;
        }
    }

    if (arr2) {
        while(*arr2 != '\0') {
            *arr3 = *arr2;
            ++arr2; ++arr3;
        }
    }

    *arr3 = '\0';
}

Answer 3

您應該嘗試按索引連接索引。在下面的代碼中，我首先在arr3添加arr1所有內容，然后將arr2內容與arr3

#include <iostream>

using namespace std;

void Concat(char arr1[], char arr2[], char arr3[]);

int main(){

    char arr1[] = {"Hello how are you? \0 "};
    char arr2[] = { "The weather was cloudy today, so it rained. \0" };
    char arr3[] = { "Coffee is a great way to start the day. \0" };

    Concat(arr1, arr2, arr3);
    std::cout << "arr3 is " << arr3 << std::endl;
}

void Concat(char arr1[], char arr2[], char arr3[]){

   if (arr1) {
        while(*arr1 != '\0') {
            *arr3 = *arr1;
            ++arr1; ++arr3;
        }
    }

    if (arr2) {
        while(*arr2 != '\0') {
            *arr3 = *arr2;
            ++arr2; ++arr3;
        }
    }

    *arr3 = '\0';


}