Question

输入正整数n，计算1-1/3+1/5-1/7+....的前n项之和。用C语言程序解答

Answer 1

#include <stdio.h>
main( )
{
int denominator , flag，i, n;
double item,sum;
printf(“Enter n:”);
scanf(“%d”,&n);
denominator = 1;
flag=1;
sum = 0
for(i = 1; i<=n ; i++){
item=flag*1.0/denominator ;
sum=sum +item;
flag=-flag ;
denominator= denominator+2;
}
printf（“Sum=%.2f\n”,sum）;
}

运行示例：
Enter n：2
Sum=0.67

Answer 2

#include <stdio.h>
main( )
{
int denominator , flag，i, n;
double item,sum;
printf(“Enter n:”);
scanf(“%d”,&n);
denominator = 1;
flag=1;
sum = 0
for(i = 1; i<=n ; i++){
item=flag*1.0/denominator ;
sum=sum +item;
fla
g=-flag ;
denominator= denominator+2;
}

printf（“Sum=%.2f\n”,sum）;
}