11.14 two-dimensional array

2. seeking a 3 × 3 matrix of diagonal elements of the sum, product, upper triangular, lower triangular element and the.

#include <stdio.h>
#define  N  3
int main()
{
	int i,j,sum,ji,s3,x3;
	sum=0,ji=1,s3=0,x3=0;
	int a[N][N]={{1,2,3},{4,5,6},{7,8,9}};
	printf("3x3矩阵\n");
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			printf("%3d",a[i][j]);
		}
		printf("\n");
	}
	for(i=0;i<3;i++)
	{
	for(j=0;j<3;j++)
	if(i<=j)
	{
	s3+=a[i][j];
	 }
	}
	for(i=0;i<3;i++)
	{
	for(j=0;j<3;j++)
	if(j<=i)
	{
	x3+=a[i][j];
	 }
	}
	for(i=0;i<3;i++)
	{
	for(j=i;j<3;j++)
	if(i==j)
	{
	sum=sum+a[i][j];
	ji=ji*a[i][j];
	 } 
	}
	printf("和=%d 积=%d 上三角和=%d 下三角和=%d",sum,ji,s3,x3);
}

6. Write a program seeking the rows and columns of a two-dimensional array of elements and. ( Program in question?)

#include <stdio.h>
#define  N  3
int main()
{
	int i,j,sum;
	sum=0;
	int a[N][N]={{1,2,3},{4,5,6},{7,8,9}};
	printf("3x3矩阵\n");
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			printf("%3d",a[i][j]);
		}
		printf("\n");
	}
	for(i=0;i<3;i++)
	{
	for(j=0;j<3;j++)
	sum=sum+a[i][j];
	 } 
	printf("和=%d",sum);
	}

1. Enter a positive integer n (1≤n≤10), generates n × n matrix according to the following equation, and then outputs the matrix.

 A[i][j]=i×n+j+1

#include <stdio.h>
int main()
{
	int i,j,n;
	scanf("%d",&n);
	int a[n][n]={0};
	for(i=0;i<n;i++)
	{
	for(j=0;j<n;j++)
	{
	  a[i][j]=i*n+j+1;
	  printf("%4d",a[i][j]);
	}
	 printf("\n");
	 } 
}

3. Print the following Triangle (required to print out 10 lines).

1

1 1

1 2 1

1 3 3 1

1 4 6 4 1

1 5 10 10 5 1

…… …… ……

4. The programming to achieve B = A + A ', i.e. the transpose of the matrix A plus A and B are stored in the matrix.

#include<stdio.h>
int main()
{
    int i,j,n,a[3][3],b[3][3];
    n=0;
    printf("请输入一个矩阵A:\n");
    for(i=0;i<3;i++)
        {
            for(j=0;j<3;j++)
            scanf("%d",&a[i][j]);
        }
    printf("请输入一个矩阵A的转置:\n");
    for(j=0;j<3;j++)
        {
            for(i=0;i<3;i++)
            scanf("%d",&a[j][i]);
        }
    for(i=0;i<3;i++)
        {
            for(j=0;j<3;j++)
            b[i][j]=a[i][j]+a[j][i];
        }
    printf("矩阵B为：\n");
    for(i=0;i<3;i++)
    {
for(j=0;j<3;j++)
{
printf("%3d",b[i][j]);
}
printf("\n");
}
return 0;
}

5. Write a program seeking a two-dimensional array of elements and the four sides.

7. If the matrix A is non-boundary elements A [i] [j] is greater than four vertically and horizontally adjacent element, said A [i] [j] is the local maximum value matrix. Programming matrix output all local maxima. Matrix shall be determined by the experimenter.

8. programming, to achieve a sum of two squares (sum of the corresponding element), the difference (corresponding to difference of the element), the product of. The product of two matrices is given by C = A × B:

c ij = k = 0 p a i k × b k j = a i 0 × b 0 j + a s [1] × b 1 j + ... + a [i] [n] × b [i] [j] .