c语言4-13 求1到n的和
1、while语句
#include <stdio.h>
int main(void)
{
int i, sum = 0;
puts("please input an integer.");
do
{
printf("i = "); scanf("%d", &i);
if (i <= 0)
puts("the range of i is: > 0. ");
}
while (i <= 0);
printf("the sum of 1 to %d is: ", i);
while (i > 0)
{
sum += i;
i--;
}
printf("%d\n", sum);
return 0;
}
2、while语句;
#include <stdio.h>
int main(void)
{
int i = 1, j, sum = 0;
puts("please input an integer.");
do
{
printf("j = "); scanf("%d", &j);
if (j <= 0)
puts("the range of j is: > 0 ");
}
while (j <= 0);
printf("the sum of 1 to %d is: ", j);
while (i <= j)
{
sum += i;
i++;
}
printf("%d\n", sum);
return 0;
}
3、for语句
#include <stdio.h>
int main(void)
{
int i, sum = 0;
puts("please input an integer.");
do
{
printf("i = "); scanf("%d", &i);
if (i <= 0)
puts("the range of i is : > 0 ");
}
while (i <= 0 );
printf("the sum of 1 to %d is: ", i);
for (i; i > 0; i--)
{
sum += i;
}
printf("%d\n", sum );
return 0;
}
4、for语句
#include <stdio.h>
int main(void)
{
int i, j, sum = 0;
puts("please input an integer.");
do
{
printf("j = "); scanf("%d", &j);
if (j <= 0)
puts("the range of j is: > 0. ");
}
while (j <= 0);
printf("the sum of 1 to %d is: ", j);
for (i = 1; i <= j; i++)
{
sum += i;
}
printf("%d\n", sum);
return 0;
}
5、do语句
#include <stdio.h>
int main(void)
{
int i, sum = 0;
puts("please input an integer.");
do
{
printf("i = "); scanf("%d", &i);
if (i <= 0)
puts("the range of i is: > 0 ");
}
while (i <= 0);
printf("the sum of 1 to %d is: ", i);
do
{
sum += i;
i--;
}
while (i > 0);
printf("%d\n", sum);
return 0;
}
6、do语句
#include <stdio.h>
int main(void)
{
int i = 1, j, sum = 0;
puts("please input an integer.");
do
{
printf("j = "); scanf("%d", &j);
if (j <= 0)
puts("the range of j is: > 0 ");
}
while (j <= 0);
printf("the sum of 1 to %d is: ", j);
do
{
sum += i;
i++;
}
while (i <= j);
printf("%d\n", sum);
return 0;
}