各位!!有谁可能帮帮忙呀!!

for(int i=0;i<5;i++) // matrix
cout<<endl;
for(int j;j<5;j++)
a[i][j]=++num;

(1)
for(int i=0;i<5;i++) // part of the element triangle
for(int j;j<=i;j++)
cout<<a[i][j]<<endl;

(2)
for(int i=0;i<5;i++)

cout<<"The left catercorner's element is"<<arr[i][i]<<endl;

for(int i=0;i<5;i++)
for(int j=4;j>=0;j--)
{
if(i+j==4)
cout<<"The right catercorner's element is"<<arr[i][j]<<endl;
}

呵呵，还是你比较细心，cout<<endl;这个多写了，thank you !
#include<iostream>
#include <iomanip>
using namespace std;
int main()
{
int count=0,sum1=0,sum2=0,;
int arr[5][5];
for(int i=0;i<5;i++)
for(int j=0;j<5;j++)
arr[i][j]=++count;
for(int i=0;i<5;i++)
{
cout<<endl;
for(int j=0;j<5;j++)
cout<<setw(5)<<arr[i][j]<<" ";
cout<<endl;


}
for(int i=0;i<5;i++)
for(int j=0;j<=i;j++)

cout<<arr[i][j]<<endl;
for(int i=0;i<5;i++)

cout<<"The left catercorner's element is"<<arr[i][i]<<endl;
for(int i=0;i<5;i++)
for(int j=4;j>=0;j--)
{
if(i+j==4)
cout<<"The right catercorner's element is"<<arr[i][j]<<endl;
}
system("pause");
return 0;
}
gcc：
OUTPUT

1 2 3 4 5

6 7 8 9 10

11 12 13 14 15

16 17 18 19 20

21 22 23 24 25
1
6
7
11
12
13
16
17
18
19
21
22
23
24
25
The left catercorner's element is1
The left catercorner's element is7
The left catercorner's element is13
The left catercorner's element is19
The left catercorner's element is25
The right catercorner's element is5
The right catercorner's element is9
The right catercorner's element is13
The right catercorner's element is17
The right catercorner's element is21