//求梯形面积
#include <stdio.h>
void main()
{
float a,b,h,area;
printf("please input a,b,h\n");
scanf("%f,%f,%f",&a,&b,&h);
area = (a + b)*h/2;
printf("area = %f\n",area);
}
#include <stdio.h>
//小写转大写
void main()
{
char ch;
ch = getchar();
ch = ch - 32;
putchar(ch);
}
#include <stdio.h>//大写转小写
void main()
{
char ch;
ch = getchar();
ch = ch + 32;
putchar(ch);
}
//switch语句
#include <stdio.h>
void main()
{
char ch;
ch = getchar();
switch(ch)
{
case 'A':printf("A");break;
case 'B':printf("B");break;
default:printf("qita");
}
}
//while循环
#include <stdio.h&g