输出BOY

include <stdio.h>

int main ()
{
char a=‘B’,char b=‘O’,char c=‘Y’;
putchar(a);
putchar(b);
putchar©;
putchar(’\n’);
return 0;
}

include <stdio.h>

int main ()
{
int a=66,b=79,c=89;
putchar(a);
putchar(b);
putchar©;
putchar(’\n’);
return 0;
}

例3.9从键盘上输出BOY3个字符，然后把它们输到屏幕上

include <stdio.h>

int main ()
{
char a,b,c;
a=getchar();
b=getchar();
c=getchar();
putchar(a);
putchar(b);
putchar©;
putchar(’\n’);
return 0;
}

include <stdio.h>

int main ()
{
putchar(getchar());
putchar(getchar());
putchar(getchar());
putchar (’\n’);
return 0;
}

例3.10改写3.3的程序，是指可以适用于任何大写字母，从键盘上输入大写字母，在显示屏上输出该小写字母

include<stdio.h>

int main()
{
char c1,c2;
c1=getchar();
c2=c1+32;
putchar (c2);
putchar(’\n’);
return 0;
}

include <stdio.h>

int main ()
{
char c1,c2;
c1=getchar();
c2=c1+32;
printf (“大写字母:%c\n小写字母：%c\n”.c1,c2);
return 0;
}