1.求N的阶层。
#include<stdio.h>
int main(){
int i, n, s = 1;scanf("%d", &n);
for ( i=1; i<=n; i++ ) {
s = s*i;
}
printf("%d", s);
return 0;
}
2.
#include<stdio.h>
int main()
{
int n1 = 100, n2 = 50, n3 = 10;
double k, s1 = 0.0, s2 = 0.0, s3 = 0.0;
for ( k=1; k<=n1; k++) {
s1 +=k;
}
for ( k=1; k<=n2; k++) {
s2 += k*k;
}
for ( k=1; k<=n3; k++) {
s3 += 1/k;
}
printf("sum = %15.6f\n", s1+s2+s3);
return 0;
}
%15.6f 代表输出的浮点数宽度为15位(小数点占1位),小数点后面保留6位小数,如果输出的数值不足15位,则前面用空格补足,如果超过,则按超过的实际输出;比如123456.789123只有13位,则前面需要加2个空格,如果是123123456.789123,16位,则按实际数值输出;
3.
#include<stdio.h>
int main(){
int i,j,k,n;
printf("parcissus numbers are:");
for ( n=100l n<=1000; n++){
i = n/100; //求这个数的百位数
j = n/10-i*10; //求十位数
k = n%10; //求个位数;
if ( n == i*i*i + j*j*j + k*k*k)
printf("%d", n);
}
printf("\n");
return 0;
}