递归函数求整数的和

#include<stdio.h>
int sum(int num)
{
	int sum1=num;
	if(num>1)
	{
		sum1+=sum(num-1);		
	}
	return sum1;
}
int main()
{
	int num=0;
	printf("请输入非负整数的最大值");
	scanf("%d",&num);
	//sum(num);
	printf("the sum is %d\n",sum(num));
	return 0;
}

---

方法二

#include<stdio.h>
int sum(int num)
{
    if(num==1)
    {   
        return 1;
    }
	return sum(num-1)+num;
}
int main()
{
	int num=0;
	printf("请输入非负整数的最大值");
	scanf("%d",&num);
	//sum(num);
	printf("the sum is %d\n",sum(num));
	return 0;
}