本文共 946 字，大约阅读时间需要 3 分钟。

#include
   
    int main(void){   	int i, j;	long t, s = 0;	int n;	scanf("%d", &n);	for( i = 2; i <= n; i += 2 ) {   		t = 1;		for( j = 2; j <= i; j++ ){   			t *= j;		}		s += t;	}	printf("this sum=%ld\n",s);	return 0;  }
   

第二题

#include 
   
    int main(void){   	int day, x1, x2;	day = 9;	x2 = 1;	while( day > 0 ) {   		x1 = (x2 + 1) * 2;		x2 = x1;		printf("%d\n", x1);		day--;	}	printf("the total is %d\n",x1);	return 0;}
   

第三题

#define N 11#include 
   
    int main(void){   	int i, j, t, number, a[N] = {   1,2,4,6,8,9,12,15,149,156};	printf("请输入要插入的数字：\n");	scanf("%d", &number);	printf("原数组的值");	for( i = 0; i < N - 1; i++ ) {   		printf("%5d", a[i]);	} 	printf("\n");	for( i = N - 2; i >= 0; i-- ) {   		if( number <= a[i] ) {   			a[i+1] = a[i];		}		else{   			a[i+1] = number;			break;		}	} 	if( number < a[0] ){   		a[0] = number;	}	printf("插入后的数组为：\n");	for( i = 0; i < N; i++) {   		printf("%5d", a[i]);	}	printf("\n");	return 0;}