二维数组中所有元素的总和在C中

如何解决二维数组中所有元素的总和在C中

我试图使函数将数组中的所有元素加起来，但是我一直失败。指针有问题还是其他问题？我将不胜感激。

#include <stdio.h>

int element_sum(int *data)
{
    int  x = 0; //sum of all elements
    for (int i = 0; i < 3; i++) //loop for row
    {
        for (int j = 0; j < 4; j++) //loop for column
        {
            x += &data[i][j];
            printf("%d\n",x);
        }
    }
    return x;
}

int main(void)
{
    int data[3][4] = {{22,23,123,192},{43,335,44,9},{3,93,8,7}};
    int sum; // sum 
    sum = element_sum(*data); //function 
    printf("sum = %d\n",sum);
    return 0;
}

解决方法

由于数组是连续的内存块，因此您可以对任意数量的维执行以下操作：

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

int addAll(int *arr,size_t nDim,...)
{
    va_list list;
    size_t nElem = 1;
    int result = 0;

    va_start(list,nDim);

    for(size_t dim = 0; dim < nDim; dim++)
    {
        nElem *= va_arg(list,int);
    }
    printf("Number of elelments %zu\n",nElem);

    while(nElem--) result += *arr++;

    return result;
}

int main(void)
{
    int data[3][4] = {{31,25,12,19},{3,35,4,46},{8,33,11,5}};
    int sum; // sum 
    sum = addAll(*data,2,3,4); //function 
    printf("sum = %d\n",sum);
    return 0;
}

https://godbolt.org/z/nx1139

或3D

int main(void)
{
    int data[][3][4] = {
        {{31,5}},{{31,};
    int sum; // sum 
    sum = addAll(**data,5,sum);
    return 0;
}

https://godbolt.org/z/fMx8G6

,

您不能使用指向<?php // Server information $server = "server\instance,port"; $database = "database"; $uid = "username"; $pwd = "password"; // Connection try { $conn = new PDO("sqlsrv:server=$server;Database=$database",$uid,$pwd); $conn->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION); } catch( PDOException $e ) { die( "Error connecting to SQL Server".$e->getMessage()); } // Statement $sql = " DECLARE @date VARCHAR(19) SET @date = CONVERT(VARCHAR(19),GETDATE(),126) SET @date = REPLACE(@date,':','-') SET @date = REPLACE(@date,'T','-') DECLARE @fileName VARCHAR(100) SET @fileName = ('d:\backup\BackUp_' + @date + '.bak') BACKUP DATABASE dbname TO DISK = @fileName WITH FORMAT,STATS = 1,MEDIANAME = 'SQLServerBackups',NAME = 'Full Backup of dbname'; "; try { $stmt = $conn->prepare($sql); $stmt->execute(); } catch (PDOException $e) { die ("Error executing query. ".$e->getMessage()); } // Clear buffer try { while ($stmt->nextRowset() != null){}; echo "Success"; } catch (PDOException $e) { die ("Error executing query. ".$e->getMessage()); } // End $stmt = null; $conn = null; ?> 的指针来映射2D数组，应该是：

In [539]: df.Net = df.Net.str.split(':').str[-1]

In [540]: df
Out[540]: 
  Ref  Net
0  C1  VCC
1  C2  VDD
2  C3  GND

换句话说，您至少需要知道最后一个维度，或者可以使用一维数组对其进行仿真：

int

,

将您的数组参数声明为2D数组：

int matrix_sum(int rows,int cols,int data[rows][cols]) {
    int  x = 0; 
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            x += data[i][j];
            printf("%d\n",x);
        }
    }
    return x;
}

调用很简单：

sum = matrix_sum(3,data);

请注意，这可能不适用于某些过时的编译器，因为它要求您的C编译器支持C99可变长度数组功能。