do和后面紧跟的while不要
else if(a<b)改为else
学会单步调试
else应改为else if
供参考:
#include<stdio.h>
int main()
{
int a,b,start,end;
int sum=0;
puts("请输入两个整数:");
printf("整数1:");scanf("%d",&a);
printf("整数2:");scanf("%d",&b);
do{
if(a > b)
{
start = b;
end = a;
}
else if(a < b) //修改
{
start = a;
end =b;
}
}while(start > end);//while(start <= end); 修改
while(start <= end) //修改
{
sum = start+sum;
start = start + 1;
}
printf("这两个整数之间所有整数的和为%d",sum);
return 0;
}