C/C++ 一维数组和二维数组参数传递的几种方式

一维数组：

#include <iostream>
#include <windows.h>
#include <string>
using namespace std;
//在以下几种方法中，ages都不是真正的数组，实际上是一个指针 int *ages
int calAverage1(int ages[5]) {
    printf("%d\n",sizeof(ages));
    int s = 0;
    for (int i = 0; i < 5;i++) {
        s += ages[i];
    }
    return s / 5;
}
int calAverage2(int ages[],int n) {
    printf("%d\n", sizeof(ages));
    int s = 0;
    for (int i = 0; i < n; i++) {
        s += ages[i];
    }
    return s / 5;
}
int calAverage3(int *ages) {
    printf("%d\n", sizeof(ages));
    int s = 0;
    for (int i = 0; i < 5; i++) {
        s += ages[i];
    }
    return s / 5;
}
int calAverage4(int* ages,int n) {
    printf("%d\n", sizeof(ages));
    int s = 0;
    for (int i = 0; i < n; i++) {
        s += ages[i];
    }
    return s / 5;
}
int main() {
    int p[5] = {20,30,40,50,60}; 
    //计算平均年龄
    printf("%d\n", calAverage1(p));
    printf("%d\n", calAverage2(p,5));
    printf("%d\n", calAverage3(p));
    printf("%d\n", calAverage4(p,5));
    system("pause");
    return 0;
}

二维数组：

#include <iostream>
#include <stdio.h>
#include <windows.h>
#include <string>
using namespace std;
int calAverage1(int p[3][2]) {
    // 特别注意：此时 ages 不是真正的二维数组
    // 它实际上是一个指向一维数组的指针 int (*ages)[4]
    int s = 0;
    for (int i = 0; i < 3;i++){
        for (int j = 0; j < 2; j++) {
            s += p[i][j];
        }
    }
    return s / (3*2);
}
int calAverage2(int p[][2],int n) {
    int s = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 2; j++) {
            s += p[i][j];
        }
    }
    return s / (n * 2);
}
int calAverage3(int (*p)[2],int rows) {
    int s = 0;
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < 2; j++) {
            s += p[i][j]; 
        }
    }
    return s / (rows * 2);
}
int calAverage4(int *p, int rows,int rols) {
    int s = 0;
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < rols; j++) {
            s += (*(p+i*rols+ j)); //*(p+i*rols+ j)==》*(p[i*rols+j])
        }
    }
    return s / (rows * rols);
}
int main() {
    int ages[3][2] = {
                        20,35,
                        25,63,
                        78,25
    };
    
    printf("%d\n", calAverage1(ages));
    printf("%d\n", calAverage2(ages,3));
    printf("%d\n", calAverage3(ages, 3));
    printf("%d\n", calAverage4(*ages, 3,2));
    system("pause");
    return 0;
}