while的经典用法

1. S=1+1/2+1/3+1/4+…+1/100

#include<stedio.h>main(){    double sum=0;    int i=1;    while(i<100)    {        sum=sum+1.0/i;        i++;    }    printf("%f",sum);    return 0; } 

1. s=10!

#include<stdio.h> main() {    int s=1,i=1;    while(i<=10)    {        s=s*i;        i++;     }     printf("10!=%d\n",s);     return 0; }

1. s=1-1/2+1/3-1/4+…+1/99-1/100

#include<stdio.h> main() {    double sum=0,t;    int i=1,sign=1;    while(i<=100)    {        t=sign*1.0/i;        sum=sum+t;        i++;        sign=-sign;     }     printf("s=%f",sum);     return 0; }

1. s=1!+2!+3!+…+10!

#include<stdio.h> main() {    int sum=0,i=1,t=1;    while(i<=10)    {        sum+=t;        i++;        t*=i;     }     printf("%d\n",sum);     return 0;    }