C语言再学习-002-+-*/＞＜……

Posted 2022-08-25 zhangrelay

案例1，两数相乘 

#include <stdio.h>
main()

		int x,y,m;
		printf("Please input x and y\\n");
		scanf("%d%d",&x,&y);
		m=x*y;
		printf("%d * %d = %d\\n",x,y,m);

输入，x和y，输出m为x和y的乘积。

其中*可以更换为+-/等，int也可以用float。

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案例2，比较两数大小，输出max。

#include <stdio.h>
main()

	float x,y,c;
	printf("Please input x and y:\\n");
	scanf("%f%f",&x,&y);
	c=x>y?x:y;
	printf("MAX of (%f,%f) is %f",x,y,c);

比大小或者是否相同，都可以用类似方法实现。 

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案例3：

#include <stdio.h>
main()

	char ch,nch;	
	int count;	
	int k;	

	printf("Please input a string with a # in the end.\\n");
	scanf("%c",&ch);	
	while(ch != '#')	
	
		if(ch >= '0' && ch <= '9')
		
			count = ch-'0'+1;	
			scanf("%c",&nch);	
			for(k=0;k<count;k++)	
				printf("%c",nch);
		
		else
			printf("%c",ch);	
		printf(" ");			
		scanf("%c",&ch);		
	
	printf("#\\n");			

字符串输入和输入，结束符为#。 

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案例4：

#include <stdio.h>
void main()

    printf("The bytes of the variables are:\\n");
    printf("int:%d bytes\\n",sizeof(int));

    printf("char:%d byte\\n",sizeof(char));

    printf("short:%d bytes\\n",sizeof(short));

    printf("long:%d bytes\\n",sizeof(long));

    printf("float:%d bytes\\n",sizeof(float));

    printf("double:%d bytes\\n",sizeof(double));

    printf("long double:%d bytes\\n",sizeof(long double));
    getchar();

显示各种变量所占用的字节数。

32位/64位系统是否有差异？ 

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案例5：

#include <stdio.h>
main()

	int a=5,b,c,i=10;
	b=a++;
	c=++b;

	printf("a = %d, b = %d, c = %d\\n",a,b,c);
	printf("i,i++,i++ = %d,%d,%d\\n",i,i++,i++);
	printf("%d\\n",++i);
	printf("%d\\n",--i);
	printf("%d\\n",i++);
	printf("%d\\n",i--);
	printf("%d\\n",-i++);
	printf("%d\\n",-i--);
	getchar();

所谓++，--，前前后后的各种效果。

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案例6：

#include <stdio.h>
main()

	int i,j,n;
	long sum=0,temp=0;

	printf("Please input a number to n:\\n");
	scanf("%d",&n);
	if(n<1)
	
		printf("The n must no less than 1!\\n");
		return;
	

	for(i=1;i<=n;i++)
	
		temp=0;
		for(j=1;j<=i;j++)
			temp+=j;
		sum+=temp;
	
	printf("The sum of the sequence(%d) is %d\\n",n,sum);
	getchar();
	getchar();

简单数列求和，还可以用递归方式实现。

怎么做？

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猜猜如下两段程序是啥功能？

#include <stdio.h>
#include <conio.h>
void main(void)

	int i,j,x,y;
	clrscr();
	printf("\\n\\n multiplication table \\n\\n");
	x=9;
	y=5;
	for(i=1;i<=9;i++)
	
		gotoxy(x,y);
		printf("%2d ",i);
		x+=3;
	
	x=7;
	y=6;
	for(i=1;i<=9;i++)
	
		gotoxy(x,y);
		printf("%2d ",i);
		y++;
	
	x=9;
	y= 6;
	for(i=1;i<=9;i++)
	
		for(j=1;j<=9;j++)
		
			gotoxy(x,y);
			printf("%2d ",i*j);
			y++;
		
		y-=9;
		x+=3;
	
	printf("\\n\\n");

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#include <stdio.h>
#include <conio.h>
void main()

	int Password=0,Number=0,price=58,i=0;
	clrscr();
	printf("\\n====This is a Number Guess Game!====\\n");
	while( Password != 1234 )
	
		if( i >= 3 )
			return;
		i++;
		puts("Please input Password: ");
		scanf("%d",&Password);
	

	i=0;
	while( Number!=price )
	
		do
			puts("Please input a number between 1 and 100: ");
			scanf("%d",&Number);
			printf("Your input number is %d\\n",Number);
		while( !(Number>=1 && Number<=100) );
		if( Number >= 90 )
		
			printf("Too Bigger! Press any key to try again!\\n");
		
		else if( Number >= 70 && Number < 90 )
		
			printf("Bigger!\\n");
		
		else if( Number >= 1 && Number <= 30 )
		
			printf("Too Small! Press any key to try again!\\n");
		
		else if( Number > 30 && Number <= 50 )
		
			printf("Small! Press any key to try again!\\n");
		
		else
		
			if( Number == price )
			
				printf("OK! You are right! Bye Bye!\\n");
			
			else if( Number < price )
			
				printf("Sorry,Only a little smaller! Press any key to try again!\\n");

			
			else if( Number > price )
				printf(" Sorry, Only a little bigger! Press any key to try again!\\n");
		
		getch();
	

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是乘法表和猜数字吗？？？？？？

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