while语句：

#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>
int main()
{
	int i = 1;
	double sum = 0.0;
	while(i <= 50)
	{
		sum += 1.0/i;
		i++;
	}
	printf("sum = %lf\n",sum);
	return 0;
}

 

for语句：

#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h> 
int  main()    
{       
	int i;
	double sum=0.0;    
    for(i=1;i<=50;i++)    
    {     
        sum += 1.0/i;
    }     
    printf("sum = %lf\n",sum);      
}