C语言知识点.ppt

文档介绍：#include <> /* */
void main()
{
int n = 5;
int base_num = 2; /* 数字基数*/
long t = base_num;
long sum = t;
for (int i=2;i<=n;i++)
{
t = t*10 + base_num; /* 递推公式*/
sum += t;
}
printf("t=%ld\tsum=%ld\n", t, sum);
}
#include <> /* */
void main()
{
int i;
long double t, sum;
t = 1;
sum = t;
for (i=2;i<=20;i++)
{
t *= i; /* 利用递推公式求阶乘*/
sum += t; /* 求和*/
}
printf("t=%lf\tsum=%lf\n", t, sum);
printf("t=%.0lf\tsum=%.0lf\n", t, sum);
}
#include <> /* */
void main()
{
int i, j, k, n, mid;
do {
printf("Pls input an odd integer n=: ");
scanf("%d", &n);
} while(n%2 == 0);

mid = n/2+1;
for (i=1; i<=mid; i++) { /* 输出上面mid层*/
for (j=1; j<=mid-i; j++) printf(" "); /* 空格数等于中间层数-1 */
for (k=1; k<=2*i-1; k++) printf("*"); /* *数=2*i-1 */
printf("\n");
}

for (i=mid+1; i<=n; i++) { /* 输出下面mid-1层*/
for (j=1; j<=i-mid; j++) printf(" ");
for (k=1; k<=2*(n-i)+1;k++) printf("*");
printf("\n");
}
}