把两个数的值互换：
#include <stdio.h>
main()
{
int a,b,c=0;
printf("请输入两个整数：\n");
scanf("%d%d",&a,&b);
printf("a=%d,b=%d",a,b);
c=a;a=b;b=c;
printf("a=%d,b=%d",a,b);
}
小写字母变大写字母：
#include <stdio.h>
main()
{
int d=32;
char ch1,ch2,ch3;
printf("input three better:");
ch1=getchar();
ch2=getchar();
ch3=getchar();
ch1=ch1-d;
ch2=ch2-d;
ch3=ch3-d;
ch1=ch1>'z'?ch1-26:ch1;
ch2=ch2>'z'?ch2-26:ch2;
ch3=ch3>'z'?ch3-26:ch2;
putchar(ch1);
putchar(ch2);
putchar(ch3);
getch();
}
判断大小：
#include <stdio.h>
main()
{
int a,b,min;
printf("请输入两个整数:");
scanf("%d%d",&a,&b);
if(a>b) min=b;else min=a;
\\三目运算的话， a>b ? printf("%d",b);:printf("%d",a);
printf("最小的数是%d",min);
}
求三位数的百位、十位、个位之和：
#include <stdio.h>
main()
{
int a,b,c,n,s;
printf("input numbers:");
scanf("%d",&n);
a=n%10;
c=n/100;
b=n%100/10;
s=a+b+c;
printf("%d",s);
getch();
}
