文末附运算符的优先表和ASCII表 一、算术运算符 加(+)减(—)乘(*)除(/) 模(余)运算符(%):不允许出现浮点型,余数正负取决于被除数正负 #include stdio.hint main() { int i, b, a
文末附运算符的优先表和ASCII表
一、算术运算符
- 加(+)减(—)乘(*)除(/)
- 模(余)运算符(%):不允许出现浮点型,余数正负取决于被除数正负
#include <stdio.h>
int main() {
int i, b, a, c;
i= 4, b=3;
a= i+b;
c= i*a;
float p, k;
p= i/b;
k= i%a;
printf("a=%d,c=%d,p=%f,k=%f\n",a,c,p,k);
return 0;
}
[root@chenshuyi c]# ./o
a=7,c=28,p=1.000000,k=4.000000
- 自增(++i,–i;i++,i–)
#include <stdio.h>
int main() {
int i;
i= 4;
printf("%d\n",++i);
return 0;
}
[root@chenshuyi c]# ./o
5
#include <stdio.h>
int main() {
int i;
i= 4;
printf("%d\n",i--);
//printf("%d\n",i); 输出是
return 0;
}
[root@chenshuyi c]# ./o
4
二、关系运算符
- 大于(>)小于(<)等于(==)
#include <stdio.h>
int main() {
int a, b, max;
printf ("please enter a and b\n");
scanf ("%d %d",&a, &b);
if (a>b) max=a;
if (a<b) max=b;
if (a==b) max=a;
printf ("max=%d\n",max);
return 0;
}
[root@chenshuyi c]# ./o
please enter a and b
55 66
max=66
[root@chenshuyi c]# ./o
please enter a and b
44 44
max=44
- 小于或等于(<=)大于或等于(>=)不等于(!=)赋值(-=、+=、*=);
#include<stdio.h>
int main(){
int a = 10;
a +=a *=a -=20;
printf("%d\n",a);
}
[root@chenshuyi c]# ./ass
200
#include <stdio.h>
int main() {
int a, b, max;
printf ("please enter a and b\n");
scanf ("%d %d",&a, &b);
if (a>=b) max=a;
if (a<=b) max=b;
printf ("max=%d\n",max);
return 0;
}
[root@chenshuyi c]# ./o
please enter a and b
55 66
max=66
[root@chenshuyi c]# ./o
please enter a and b
77 77
max=77
#include <stdio.h>
int main() {
int a, b, max;
printf ("please enter a and b\n");
scanf ("%d %d",&a, &b);
if (a!=b);
if (a>b) max=a;
if (a<b) max=b;
printf ("max=%d\n",max);
return 0;
}
[root@chenshuyi c]# ./o
please enter a and b
44 44
max=0
[root@chenshuyi c]# ./o
please enter a and b
44 55
max=55
三、逻辑运算符(并且、或者、除非)
PS:优先级从上至下
- 逻辑非(! NOT)
#include <stdio.h>
int main() {
int num = 0;
printf ("Please enter num value: ");
scanf("%d", &num);
if (num != 69) {
printf ("num %d is not equal to 69.\n", num);
}
return 0;
}
~
[root@chenshuyi c]# ./o
Please enter num value: 69
[root@chenshuyi c]# ./o
Please enter num value: 1
num 1 is not equal to 69.
- 逻辑与(&& AND)
#include <stdio.h>
int main() {
int a, b, x, y;
printf ("please enter a and b,x and y\n");
scanf ("a=%d,b=%d,x=%d,y=%d",&a, &b, &x, &y);
if (a==b && x==y){
printf ("a=b,x=y\n");
}
else
printf ("sorry,I donot konw.\n");
return 0;
}
[root@chenshuyi c]# ./o
please enter a and b,x and y
a=1,b=2,x=1,y=1
sorry,I donot konw.
[root@chenshuyi c]# ./o
please enter a and b,x and y
a=1,b=1,x=2,y=2
a=b,x=y
- 逻辑或(|| OR)
[root@chenshuyi c]# vim or.c
#include<stdio.h>
int main(){
int a = 1;
int b = 0;
printf("%d\n",a || (b++));
printf("%d\n",b);
}
[root@chenshuyi c]# ./or
1
0
#include<stdio.h>
int main(){
int a = 0;
int b = 0;
printf("%d\n",a || (b++));
printf("%d\n",b);
}
[root@chenshuyi c]# ./or
0
1
#include<stdio.h>
int main(){
int a = 0;
int b = 0;
printf("%d\n",a || (++b));
printf("%d\n",b);
}
[root@chenshuyi c]# ./or
1
1
- &&和||的区别
#include<stdio.h>
int main(){
printf("%d\n",1 && 1);
printf("%d\n",0 && 1);
printf("%d\n",0 && 0);
printf("%d\n",1 || 1);
printf("%d\n",0 || 1);
printf("%d\n",0 || 0);
return 0;
}
[root@chenshuyi c]# ./and
1
0
0
1
1
0
PS:优先级:算术运算符>关系运算符>赋值运算符
四、位运算符
- 右移(>>)左移(<<)
- 按位与(&)
- 按位或(|)
- 按位异或(^)
- 取反(~)
五、赋值运算符
- 等号(=)
- 扩展赋值运算符
+= 加赋值 (a += 3 等价于 a = a + 3)
-= 减赋值
*= 乘赋值
/= 除赋值
%= 求余赋值
&= 按位与赋值
| = 按位或赋值
^= 按位异或赋值
<<= 左移位赋值(>>= 右移位赋值)
<> 当右操作数又是一个赋值表达式时,形成多重赋值表达式
六、条件运算符
PS:条件运算符优先级高于赋值、逗号运算符,低于其他运算符。
- 关系表达式 ? 表达式1 : 表达式2(当表达式多了后就先从右算到左)
三目运算符:条件 ? 结果1 : 结果2(条件成立时,返回:号前的结果;不成立就返回后面的结果)
//例子:判断a小于或者大于b,输出最大值max
#include <stdio.h>
int main(){
int a, b, max;
scanf("a=%d,b=%d",&a,&b);
max=a>b?a:b;
printf("max=%d\n",max);
return 0;
}
[root@chenshuyi c]# gcc -o swap swap.c
[root@chenshuyi c]# ./swap
a=2,b=3
max=3
//例子:多个表达式
#include<stdio.h>
int main(){
int a = 300;
int b = 50;
int c = a>b? 350: a<b? 360:370;
printf("%d\n",c);
return 0;
}
[root@chenshuyi c]# ./three
350
#include<stdio.h>
int main(){
int a = 50;
int b = 300;
int c = a>b? (b-a): a<b? (a+b):370;
printf("%d\n",c);
return 0;
}
[root@chenshuyi c]# ./three
350
七、逗号运算符(,)
#include<stdio.h>
int main(){
int i = 1;
int a = (i+100,i++,i);
printf("%d\n",a);
return 0;
}
[root@chenshuyi c]# ./comma
2
#include<stdio.h>
int main(){
int i = 1;
int a = (i=i+100,i++,i);
printf("%d\n",a);
return 0;
}
[root@chenshuyi c]# ./comma
102
八、指针运算符
- 指针变量(*)
定义:基类型 * 指针变量名;
例子1:通过指针变量访问整型变量
#include <stdio.h>
int main() {
int a, b; #定义两个int变量
int * pointer_1, * pointer_2; #定义两个指针变量,指向int变量
a = 100; b = 10;
pointer_1 = &a; #把变量a的地址赋给指针pointer_1
pointer_2 = &b;
printf ("a = %d, b = %d \n", a, b);
printf (" * pointer_1 = %d, * pointer_2 = %d \n", * pointer_1, * pointer_2); #输出的指针变量所指向的整型变量的值
return 0;
}
~
[root@chenshuyi c]# gcc -o pointer1 pointer1.c
[root@chenshuyi c]# ./pointer1
a = 100, b = 10
* pointer_1 = 100, * pointer_2 = 10
[root@chenshuyi c]# vi pointer1.c
例子2:比大小
#include <stdio.h>
int main () {
int * p1, * p2, * p, a, b;
scanf ("%d, %d", &a, &b);
p1 = &a; p2 = &b;
if (a < b) {
p = p1; p1 = p2; p2 = p;
}
printf ("a = %d, b = %d\n", a, b);
printf ("max = %d, min = %d\n", * p1, * p2);
return 0;
}
r
[root@chenshuyi c]# ./pointer2
4,6
a = 4, b = 6
max = 6, min = 4
例子3:算术
#include <stdio.h>
int main () {
int maxsum = 123;
double temp = 888.8889922111111;
temp += (float)maxsum;
printf ("%7.3f, %d\n", (float)temp, (int)temp);
return 0;
}
[root@chenshuyi c]# gcc -o compulsion compulsion.c
[root@chenshuyi c]# ./compulsion
1011.889, 1011
九、求字节数运算符(sizeof)
- 当sizeof(与数据类型(如int,float,char …等)一起使用时,返回分配给该数据类型的内存量。
#include<stdio.h>
int main()
{
printf("%d\n",sizeof(char));
printf("%d\n",sizeof(int));
printf("%d\n",sizeof(float));
printf("%d\n", sizeof(double));
return 0;
}
- 当sizeof和表达式一起使用的时候,返回表达式的大小。
#include<stdio.h>
int main() {
int a = 1, b = 3;
printf ("%d\n", sizeof ( a + b ));
return 0;
}
[root@chenshuyi c]# gcc -o sizeof1 sizeof1.c
[root@chenshuyi c]# ./sizeof1
4
十、强制类型转换运算符
例1:小数转整数
#include <stdio.h>
int main () {
float f = 8.88;
int i;
i = (int) f;
printf ("f = %f, i = %d \n", f, i);
return 0;
}
[root@chenshuyi c]# gcc -o compulsion compulsion.c
[root@chenshuyi c]# ./compulsion
f = 8.880000, i = 8
例2:整数转小数
#include <stdio.h>
int main () {
int maxsum = 123;
printf ("%lf\n", (double) maxsum);
return 0;
}
[root@chenshuyi c]# gcc -o compulsion compulsion.c
[root@chenshuyi c]# ./compulsion
123.000000
十一、成员运算符
- 成员运算符(.)
- 间接成员运算符(–>)
十二、下标运算符([ ])
PS:运算符的优先级和结合性
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