C语言基础4---运算符和表达式

学习网站：C语言网.
编译器：Red Panda Dev-C++

#include
int main(void){
    int intOne;
    int intTwo;
    
    // intOne：左值，变量名；=：赋值符号；584：右值；
    intOne = 584;
    intTwo = 520;
    
    printf("intOne = %d.intTwo = %d.n", intOne, intTwo);
    
    return 0;
}

#include 
int main(void){
	int numberOne = 100;
	int numberTwo = 161;
	int numberThree = 4;
	
	// 常见的运算 
	printf("numberOne = %d numberTwo = %d numberThree = %dn", numberOne, numberTwo, numberThree);
	printf("numberOne + numberTwo = %dn", numberOne + numberTwo);
	printf("numberTwo - numberOne = %dn", numberTwo - numberOne);
	printf("numberOne * numberThree = %dn", numberOne * numberThree);
	printf("numberOne / numberThree = %dn", numberOne / numberThree);
	printf("numberTwo %% numberThree = %dn", numberTwo % numberThree);
	
	return 0;
}

#include 
int main(void){
	// 不同的定义变量方式 
	int numberOne = 8;
	int numberTwo = 8;
	int numberThree, numberFour;
	numberThree = numberFour = 8;
	
	// 自加自减运算符
	printf("The initial data：numberOne = %d numberTwo = %dn", numberOne, numberTwo);
	printf("++numberOne = %d numberTwo++ = %dn", ++numberOne, numberTwo++);
	printf("Now,numberOne = %d numberTwo = %dn", numberOne, numberTwo);
	
	printf("n");
	printf("The initial data：numberThree = %d numberFour = %dn", numberThree, numberFour);
	printf("--numberThree = %d numberFour-- = %dn", --numberThree, numberFour--);
	printf("Now,numberThree = %d numberFour = %dn", numberThree, numberFour);
	
	return 0;
}

#include 
int main(void){
	int intNumber = 1;
	float floatNumber = 3.14;
	
	int intSize1 = sizeof(intNumber);
	int floatSize1 = sizeof(floatNumber);
	
	int intSize2 = sizeof(int);
	int floatSize2 = sizeof(float);
	
	printf("The length of intSize1 = %d bytes.n", intSize1);
	printf("The length of intSize2 = %d bytes.n", intSize2);
	printf("The length of floatSize1 = %d bytes.n", floatSize1);
	printf("The length of floatSize2 = %d bytes.n", floatSize2);
	
	return 0;
}

// Tips：
// 1.逻辑运算符包括：逻辑与&&、逻辑或||、逻辑非!；
// 2.逻辑与：运算符两侧表达式均为真时，表达式为真；
// 3.逻辑或：运算符两侧表达式只要有一个为真，则表达式为真；
// 4.逻辑非：原表达式为真，则运算后为假，原表达式为假，运算后表达式为真；

#include 
int main(void){
	printf("The result of 1 && 2 is %dn", 1 && 2);
	printf("The result of 0 && 1 is %dn", 0 && 1);
	printf("The result of 1 || 2 is %dn", 1 || 2);
	printf("The result of 0 || 1 is %dn", 0 || 1);
	printf("The result of !1 is %dn", !0);
	printf("The result of !0 is %dn", !1);
	
	return 0;
}

// Tips:
// 三目运算符：表达式1?表达式2:表达式3
// 解释说明：如果表达式1的值为真，则三目运算符整体的值就是表达式2的值；
// 如果表达式1的值为假，则三目运算符整体的值就是表达式3的值；

#include 
int main(void){
	int condition1 = 0;
	int condition2 = 1;
	
	int temp1, temp2;
	
	temp1 = condition1?(condition1 + condition2):(condition1 - condition2);    // temp1返回-1;
	temp2 = condition2?(condition1 + condition2):(condition1 - condition2);    // temp2返回1;
	
	printf("The value of temp1 is %dn", temp1);
	printf("The value of temp2 is %dn", temp2);
	
	return 0;
}

#include 
int main(void){
	int numberOne = 2;
	int numberTwo = 1;
	
	printf("The result of 2 > 1 is %dn", numberOne > numberTwo);
	printf("The result of 2 < 1 is %dn", numberOne < numberTwo);
	printf("The result of 2 >= 1 is %dn", numberOne >= numberTwo);
	printf("The result of 2 <= 1 is %dn", numberOne <= numberTwo);
	printf("The result of 2 == 1 is %dn", numberOne == numberTwo);
	printf("The result of 2 != 1 is %dn", numberOne != numberTwo);
	
	return 0;
}

// Tips:
// 1.语句是组成C程序的基本单位，由表达式构成；
// 2.表达式由运算符和操作数组合构成，如：1 + 2,sum = a + b
// 3.语句用结束处的一个分号表示，即表达式后面加一个分号构成一个语句，如：sum = 1 + 2;

#include 
int main(void){
	float pi = 3.1415;
	float radius;
	float circleSquare, circleCircumference;
	
	printf("Please input the radius of circle:n");
	scanf("%f",&radius);
	
	circleSquare = pi * radius * radius;
	circleCircumference = 2 * pi * radius; 
	
	printf("The square of circle is %fn", circleSquare);
	printf("The circumference of circle is %fn", circleCircumference);
	
	return 0;
}