C++ 数组元素操作

数组元素的移除

• 核心思路：创建一个新的内存空间存储移除后的数组，再将原数组delete释放，再将指针指向新数组。

cout << "----------------------------- 数组元素的移除 -------------------------" << endl;
//cout << deleteArrByIndex(0, arr11) << endl;
 
// 示例数组
int * pArr = new int[5] {1,3,5,7,9};
int * pNewArr = new int[4];
int deleteIndex = 2;    // 移除下标为2的元素
int len = 5;
for (int i = 0; i < len; ++i) {
    if(i == 2) {
        continue;
    }
    if(i <= 2) {
        pNewArr[i] = pArr[i];
    }else {
        pNewArr[i - 1] = pArr[i];
    }
}
delete[] pArr;  // 回收老数组的空间
 
pArr = pNewArr; // 将老数组的指针指向新数组的内存空间
// 打印删除后的数组
for (int i = 0; i < 4; ++i) {
    cout << pArr[i] << endl;
}

数组元素的插入

        int * pArr2 = new int[]{1,2,3,4,5};  // 1  , 3下标插入 0
        int * pInsert = new int[7];
        int offset =  0;
        for (int i = 0; i < 5; ++i) {
            if(i == 1 || i == 3) {
                pInsert[i + offset] = 0;
                offset ++;
            }
            
            pInsert[i + offset] = pArr2[i];
        }
        delete[] pArr2;
        pArr2 = pInsert;
        for (int i = 0; i < 7; ++i) {
            cout << "pArr2[" << i << "] = " << pArr2[i] << endl;
        }