小白，尝试用while，for ，if语句表示1到100相加的和。

#include <stdio.h>
int main()
{
	int a = 1;
	int sum = 0;
	while (a <= 100)
	{
		sum = sum + a;
		a++;
	}
	
	printf("总和=%d\n", sum);
	return 0;
}

#include <stdio.h>
int main()
{
	int a = 0;
	int sum = 0;
	{
		for (a = 1; a <= 100; a++)
			sum += a;
	}
	printf("总和=%d", sum);
	return 0;
}

# include <stdio.h>
int main()
{
	int a = 0;
	int sum1 = 0;
	int sum2 = 0;
	int sum3 = 0;
	for (a = 1; a <= 100; a++)
	{
		if (a % 2 == 0)
			sum1 = sum1 + a;
		else
			sum2 = sum2 + a;
	}
	sum3 = sum2 + sum1;
	printf("总和=%d\n", sum3);
	return 0;
}