2020.02.08

//用循环的方法构造一个5行5列的二维数组,
//使主对角线上的变量为1,其他为0,并将数
//组中所有项按行按列显示出来
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int a[5][5], i, j;
int main( ) {
 for (i = 0; i < 5; i++)
  for (j = 0; j < 5; j++) {
   if (i == j)
    a[i][j] = 1;
   else
    a[i][j] = 0;
  }
 for (i = 0; i < 5; i++){
  for (j = 0; j < 5; j++) 
   printf("%5d", a[i][j]);
   printf("\n");
  }
 system("pause");
}

//求一个3*3矩阵主对角线元素之和,从键盘输入矩阵
//元素的值并输出和的值
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int a[3][3], i, j, s = 0;
int main( ){
 printf("请输入元素的值\n");
 for (i = 0; i < 3; i++) 
 for (j = 0; j < 3; j++)
   scanf("%d", &a[i][j]);
   for(i=0;i<3;i++)
    s += a[i][i];
  printf("对角线元素之和为:%d\n", s);
 system("pause");
 return 0;
}

//输入n的值,n代表行数,输出如图所示的图形
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int n, i, j;
int main() {
 printf("请输入行数:\n");
 scanf("%d", &n);
 for (i = 0; i < n; i++) {
  for (j = 0; j <= i; j++)
   printf("*");
   printf("\n");
 }
 system("pause");
}

//从键盘输入30名学生的成绩数据,求其中最高分
//最低分和平均分.
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int score[30], max, min, sum = 0, adv, n;
int function1() {
 for (n = 1; n < 30; n++) {
  while (score[n] > score[n + 1])
   max = score[n];
 }
 return max;
}
int function2() {
 for (n = 1; n < 30; n++) {
  while (score[n] < score[n + 1])
   min = score[n];
 }
 return min;
}
int function3() {
 for (n = 1; n < 30; n++)
  sum += score[n];
 adv = sum / 30;
 return adv;
}
int main() {
 for (n = 0; n < 30; n++)
  scanf("%d", &score[n]);
 max = score[0];
 min = score[0];
 adv = score[0];
 for (n = 1; n < 30; n++) {
  if (score[n] > score[n + 1])
   max = score[n];
  if (score[n] < score[n + 1])
   min = score[n];
  sum += score[n];
  adv = sum / 30;
 }
 printf("最大值:\n%d最小值:\n%d平均值:\n%d", max, min, adv);
 system("pause");
}