C函數和數組

Question

我學習C語言編程並通過陣列多種功能，不知道什麼時候，爲什麼我的陣列是由東西覆蓋，幫我調試，並當場我的錯誤代碼：

#include <stdio.h> 

int insertNumbers(int *numbers, int howManny){ 
    int i; 

    for(i=0; i< howManny; i++){ 
     printf("Insert number:"); 
     scanf("%d", &numbers[i]); 
    } 
    printf("\nNumbers :(insertNumbers function)\n"); 
    for (int i = 0; i < howManny; ++i) { 
     printf("%d: %d\n",i, numbers[i]); 
    } 
    return *numbers; 
} 

int add(int *numbers, int howManny){ 
    int sum = 0; 
    for (int i = 0; i < howManny; ++i) { 
     sum = sum + numbers[i]; 
    } 
    return sum; 
} 

void printArray(int *numbers, int howManny){ 
    printf("\nNumbers:(print array function)\n"); 
    for (int i = 0; i < howManny; ++i) { 
     printf("%d: %d\n",i, numbers[i]); 
    } 
} 

int main(){ 
    int numbers, howManny, sum = 0, numbersArray; 
    printf("How manny numbers do you want?"); 
    scanf("%d", &howManny); 

    numbersArray = insertNumbers(&numbers, howManny); 

    sum = add(&numbers, howManny); 
    printf("Total sum is: %d",sum); 

    printArray(&numbersArray, howManny); 


    return 0; 
} 

結果是

How manny numbers do you want?3 
3 
Insert number:10 
10 
Insert number:20 
20 
Insert number:30 
30 

Numbers :(insertNumbers function) 
0: 10 
1: 20 
2: 30 
Total sum is: 60 
Numbers:(print array function) 
0: 10 
1: 3 
2: 10 

看起來像我的數組的地方，但不知道什麼時候，爲什麼覆蓋

甚至當我嘗試使用

printArray(&numbers, howManny); 

仍然沒有工作，但得到10，10，50值

Answer 1

您的陣列尚未在編譯時創建的。此外，數組大小在程序運行時給出。因此，數組不能是靜態的，所以它必須動態分配，並在最後釋放，以便正常工作。

這就是說，在這裏我寫了一個簡單的解決方案，你想要實現的。

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

void insertNumbers(int *numbers, int howManny){ 
    int i; 

    for(i=0; i< howManny; i++){ 
     printf("Insert number:"); 
     scanf("%d", &numbers[i]); 
    } 
    printf("\nNumbers :(insertNumbers function)\n"); 
    for (int i = 0; i < howManny; ++i) { 
     printf("%d: %d\n",i, numbers[i]); 
    } 
} 

int add(int *numbers, int howManny){ 
    int sum = 0; 
    for (int i = 0; i < howManny; ++i) { 
     sum = sum + numbers[i]; 
    } 
    return sum; 
} 

void printArray(const int *numbers, int howManny){ 
    printf("\nNumbers:(print array function)\n"); 
    for (int i = 0; i < howManny; ++i) { 
     printf("%d: %d\n",i, numbers[i]); 
    } 
} 

int main(){ 

    int *numbers, howManny; 

    printf("How manny numbers do you want?"); 
    scanf("%d", &howManny); 

    // allocate memory (dynamic allocation) 
    numbers = (int *)malloc(sizeof(int) * howManny); 

    // validate memory allocation 
    assert(numbers != NULL); 

    // numbers is modified and returned by reference 
    insertNumbers(numbers, howManny); 

    printf("Total sum is: %d", add(numbers, howManny)); 
    printArray(numbers, howManny); 

    // free dynamic allocation 
    free(numbers); 

    return 0; 
}