考试的题目

1，1+（1+2）+（1+2+3）+...+（1+...+50）

include<stdio.h>

int main()
{
int i,n=0,m=0;
for(i=1;i<=50;i++)
{
n+=i;
m+=n;
}
printf("%d\n",m);
return 0;
}
2.字母金字塔
int main()
{
int i, j, k;
char ch;
ch = 'A';
for (j = 1; j <= 4; j++)
{for (k = 1; k <= 4 - j; k++)
{
printf(" ");
}

printf("%c", ch + j - 1);
if (j != 1)
{
	for (i = 1; i <= 2 * (j - 1)-1; i++)
		printf(" ");
	printf("%c", ch + j - 1);

}
printf("\n");

}
ch = 'D';
for (j=1; j <4; j++)
{
for (k = 3; k >= 4 - j; k--)
{
printf(" ");
}
printf("%c", ch -j);
if (j != 3)
{
for (i = 1; i <= (-2)j+5; i++)
printf(" ");
printf("%c", ch -j);
}
printf("\n");
}
return 0;
}
3.ABCD=DC*BA

include<stdio.h>

int main()
{
int a, b, c, d, i = 0;
for (a = 0; a <= 9; a++)
for (b = 0; b <= 9; b++)
for (c = 0; c <= 9; c++)
for (d = 0; d <= 9; d++)
if ((a10 + b)(c10 + d)) == ((b10 + a)(d10 + c))
{
printf("%d%d=%d%d", a10 + b, c10 + d, b10 + a, d10 + c);
i++;
if (i % 5 == 0)
printf("\n");
}
return 0;
}
4.随机数

include<stdio.h>

include<stdlib.h>

include<time.h>

int main()
{
int a, i, b;
srand(time(0));
a = rand();
for (i = 1; i <= 99; i++) {
b = rand();
if (a > b)
a = b;
}
printf("%d", a);
return 0;
}