使用分支结构判断数值非零及奇偶
/*
* filename: if.c
*
* function: if/if-else
*
* data: 2011-10-26 by YourName
*
*/
#include <stdio.h>
int main(int argc, const char *argv[])
{
int x;
printf("enter a number:");
scanf("%d", &x);
//if
if (x != 0)
{
printf("x is nonzero.\n");
}
//judge a num is even or odd
if (x % 2 == 0)
{
printf("x is even.\n");
}
else
{
printf("x is odd.\n");
}
return 0;
}基本的if/else分支结构
/*
* filename: if_else.c
*
* function: if...else
*
* date: 2011-10-26
*
*/
#include <stdio.h>
int main(int argc, char *argv[])
{
if (15%4 == 15/4)
printf("equal!\n");
else
printf("Not equal!\n");
return 0;
}判断从键盘输入的3个数哪个最大
/*
* filename: max_3.c
*
* function: max of 3 num
*
* author: YourName
*
* version: 0.1
*
* date: 2011-10-26
*
*/
#include <stdio.h>
int main(int argc, const char *argv[])
{
int max, a, b, c;
printf("Please input 3 num:");
scanf("%d %d %d", &a, &b, &c);
max = a;
if (max < b)
max = b;
if (max < c)
max = c;
printf("max of 3 num is : %d\n", max);
return 0;
}从键盘输入3个整数，判断他们是否能够构成三角形
/*
* filename: triangle.c
*
* function: find a triangle
*
* date: 2011-10-26
*
*/
#include <stdio.h>
int main(int argc, const char *argv[])
{
int a, b, c;
printf("Please inout 3 num:");
scanf("%d %d %d", &a, &b, &c);
if ((a < 0) || (b < 0) || (c < 0))
{
printf("Invariable input!\n");
}
else
{
if (((a + b) > c) && ((a + c) > b) && ((b + c) > c))
{
printf("a = %d, b = %d, c = %d can found a triangle\n", a, b, c);
}
else
{
printf("a = %d, b = %d, c = %d can not found a triangle\n", a, b, c);
}
}
return 0;
}按照如下结构输入数据并根据输入的运算符完成四则运算，比如有如下输入：
3 + 5 程序执行完后输出8
3 * 7 程序执行完后输出21
/*
* filename: switch-case.c
*
* function: switch-case complete + - * / %
*
* author: Yourname
*
* version: 0.1
*
* date: 2011-10-26
*
*/
#include <stdio.h>
int main(int argc, char *argv[])
{
int a, b;
char c;
printf("please input(num1 + num2):");
scanf("%d %c %d", &a, &c, &b);
switch (c)
{
case '+':
printf("%d %c %d = %d\n", a, c, b, a + b);
break;
case '-':
printf("%d %c %d = %d\n", a, c, b, a - b);
break;
case '*':
printf("%d %c %d = %d\n", a, c, b, a * b);
break;
case '/':
printf("%d %c %d = %d\n", a, c, b, a / b);
break;
case '%':
printf("%d %c %d = %d\n", a, c, b, a % b);
break;
default:
printf("Invalid input!\n");
break;
}
return 0;
}输入数字通过switch/case分支转换为成绩级别的描述
/*
* filename: switch_grade.c
*
* function: enter a grade and print a description
*
* author: YourName
*
* version: 0.1
*
* date: 2011-10-27
*
*/
#include <stdio.h>
int main(int argc, const char *argv[])
{
int grade;
while (1)
{
printf("Please enter grade(0-4): ");
scanf("%d", &grade);
switch (grade)
{
case 4:
printf("Excellent\n");
break;
case 3:
printf("Good\n");
break;
case 2:
printf("Averge\n");
break;
case 1:
printf("Poor\n");
break;
case 0:
printf("Failing\n");
break;
default:
printf("Illegal grade\n");
break;
}
if ((grade < 0) || (grade > 4))
break;
}
return 0;
}