学C语言的第三天30个练习

[C] 纯文本查看 复制代码

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<stdlib.h>
#include <math.h>
#define ok 0
#define PI 3.14//定义一个全局常量
int main01() {

	printf("你好呀\n");
	printf("小哥哥");
	return 0;
}
int main02() {
	
	//system("mspaint");
	//system("calc");
	//system("cmd");
	//system("G://QQ浏览器下载//1.jpg");
	//system("javac");
	//system("C:/Windows10Upgrade/Windows10UpgraderApp.exe");
	printf("123");
	system("pause");
	return 0;
}
int main03() {
	int a = 1;
	int b = 2;
	int c = 3;
	c = a + b;
	printf("%d\n", c);
	return 0;
}
int main04() {
	char buff[1024] = "";
	sprintf(buff, "5678");
	printf("buff=%s",buff);
	return 0;
}
int main05() {

	const int b = 10;
	extern int a;
	int* p = &b;
	printf("p=%x\n",p);
	*p = 100;
	printf("b=%d\n", b);
	printf("%d\n",b);
    int c=	&b;
	printf("%x\n",c);
	scanf("%d\n", &b);
	printf("%d\n",b);
	return 0;
}
int main06() {
	int r=0;
	printf("请输入半径\n");
	scanf("%d", &r);
	printf("%d\n", r);
	printf("%lf\n",r*PI*r);
	return 0;
}
int main07() {
	int num = 0x80000001;
	//1000 0000 0000 0000 0000 0000 0000 0001
	//反码1111 1111 1111 1111 1111 1111 1111 1110
	//原码1111 1111 1111 1111 1111 1111 1111 1111  -2147483647
	printf("%d\n", num);
	return 0;
}
int main08() {
	int a = 10;
	int b = 020;
	int c = 0x89;
	printf("a=%d\n", a);
	printf("b=%o\n", b);
	printf("c=%x\n", c);
	printf("c=%#x\n", c);
	printf("c=%#X\n", c);
	return 0;
}
int main09() {
	int a = 10;
	//001 000

	int b = 020;
	//010 000
	int c = 0x89;
	//1000 1001
	//128  8  1
	//十进制
	printf("a=%d\n", a);
	printf("b=%d\n", b);
	printf("c=%d\n", c);
	//八进制
	/*
	 8 10
	   1  2
	8  0  1
	*/
	printf("a=%o\n", a);
	printf("b=%o\n", b);
	/*
	010 001 001
	2    1   1
	
	*/
	printf("c=%o\n", c);
	//十六进制
	printf("a=%x\n", a);
	/*
	16 10
	   0   10  A
	*/
	printf("b=%x\n", b);
	/*
	0001 0000
	1     0
	*/
	printf("c=%x\n", c);
	return 0;
}
int main10() {
	char num = 0x81;
	unsigned sum = 0x82;
	//0000 0000 0000 0000 0000 0000 1000 0010
	// 	                            128     2
	//1000 0001 
	//1111 1110
	//1111 1111
	printf("%d\n", num);//-127
	printf("%ud\n", num);//4294967169d
	printf("unsigned\n");
	printf("%d\n", sum);//130
	printf("%ud\n", sum);//130
	return 0;
}
int main11() {
	//定义无符号int变量d，以16进制方式赋值
	unsigned	int d = 0xffffffff;
	//     1111 1111 1111 1111 1111 1111 1111 1111
	//反码:1000 0000 0000 0000 0000 0000 0000 0000
	//补码:1000 0000 0000 0000 0000 0000 0000 0001
	printf("%d\n", d);
	printf("%ud\n", d);
	return 0;
}
int main12() {
	printf("int=%d\n", sizeof(int));
	printf("double=%d\n", sizeof(double));
	printf("float=%d\n", sizeof(float));
	printf("short=%d\n", sizeof(short));
	printf("char=%d\n", sizeof(char));
	printf("long=%d\n", sizeof(long));
	printf("long long=%d\n", sizeof(long long));
	return 0;
}
int main13() {
	int a = 0;
	int b = 0;
	scanf("%d %d", &a, &b);
	printf("%d\n", a);
	printf("%d\n", b);
	return 0;
}
int main14() {
	short a = 10;
	short b = 20;
	printf("%hd\n", a);
	printf("%hd\n", b);
	return 0;
}
int main15() {
	char a = "a";
	char b = "9";
	char c = "b";
	printf("%d\n",a);
	a = a + 1;
	printf("%d\n",c);
	printf("%d\n",b);
	return 0;
}
int main16() {
	char ch = 'A';
	ch = ch + 1;
	printf("%c\n",ch);
	return 0;
}
int main17() {
	char ch = 'a';
	int length = sizeof(ch);
	printf("%d\n", length);
	printf("%d\n", sizeof('a'));//字符在内存中以二进制的形式存储
	return 0;
}
int main18() {
	char a = ' ';
	a = a + ' ';
	printf("%c\n", a);
	return 0;
}
int main19() {
	char a = 0;
	char b = 0;
	scanf("%c\n", &a);
	scanf("%c\n", &b);
	printf("%d\n", a);
	printf("%d\n", b);
	printf("%c\n", a+1);
	printf("%c\n", b+2);
	return 0;
}
int main20() {
	int i = 0;
	int sum = 0;
	//求1+2+...+100的和
	while (i<100)
	{
		i++;
		sum = sum + i;
		
	}
	printf("%d\n", sum);
	return 0;
}
int main21() {
	int i = 0;
	int sum = 0;
	do 
	{
		sum += i;
		i++;
	} while (i<=100);
	printf("%d\n", sum);
	return 0;
}
int main22() {
	int i = 0;
	int sum = 0;
	for (; i<=100; i++)
	{
		sum += i;
	}
	printf("%d\n", sum);
	return 0;
}
int main23() {
	int a = 0;
	int b = 0;
	for (a=0;a<=2;a++ )
	{
		for (b=0;b<=3;b++)
		{
			for (int c=0;c<=4;c++)
			{
				printf("a=%db=%dc=%d\n", a, b, c);
			}
		}
	}
	return 0;
}
int main24() {
	int a = 0;
	int b = 0;
	int c = 0;
	while (a<=3)
	{
		while (b<=4)
		{
			c = 0;
			while (c<=5)
			{
				printf("a=%db=%dc=%d\n", a, b, c);
				c++;
			}
		}
		a++;
		b++;
	}
	return 0;
}
int main25() {
	int oushu[60] ;
	int jishu[60];
	int i = 0;
	int k = 0;
	for (int a=0;a<100;a++)
	{
		if (a % 2 != 0) {
			oushu[i] = a;
			i++;
		}
		if (a % 2 == 0) {
			jishu[k] = a;
			k++;
		}

	}
	int size= sizeof(oushu) / sizeof(oushu[0]);
	int size1 = sizeof(jishu) / sizeof(jishu[0]);
	//printf("%d\n", size);
	//printf("%d\n", size1);
	for (i=0;i<sizeof(oushu)/sizeof(oushu[0]);i++)
	{
		if (oushu[i]<0)
		{
			break;
		}
		printf("%d", oushu[i]);
		printf("%s", ",");
	}
	printf("\n");
	for (int j=0;j<sizeof(jishu)/sizeof(jishu[0]);j++)
	{
		if (jishu[j]<0)
		{
			break;
		}
		printf("%d", jishu[j]);
		printf("%s", ",");
	}
	printf("\n");
	return 0;
}
int main26() {
	goto hello;
	printf("我会执行吗?");
hello: {
	printf("hello");
	return ok;
	}
	return 0;
}
int main27() {
	int a = 0;
	int b = 0;
	char g[10];
	printf("请输入第一个数:");
	scanf("%d", &a);
	printf("请输入第二个数:");
	scanf("%d", &b);
	printf("%s\n", a > b?("第一个数大于第二个数"):("第一个数小于第二个数"));
	return ok;
}
int main28() {
	char a[] = "hello";
	char c = 0;
	for (int b=0;b< pow(2, (sizeof(char) * 7)) - 1;b++)
	{
		c += 1;
		printf("%c", c);
		printf("\n");
	}
	printf("%s", a);
	return ok;
}
int main29() {
	char a[] = {'1','2','0'};//120烫烫泰辟?齓
	char b[] = { 'a','g','f',0 };//agf
	char c[] = { 'a','g','f',1 };//agf
烫烫烫烫120烫烫泰辟?齓
	char d[] = { 'g','t','a','\0' };//gta
	char f[] = { 'g','r','s',"\0" };//grs
	printf("%s\n", a);
	printf("%s\n", b);
	printf("%s\n", c);
	printf("%s\n", d);
	printf("%s\n", f);
	return ok;
}
int main() {
	char a = "";
	char b[10]="";
	scanf("%c", &a);
	scanf("%s", b);
	printf("%c\n", a);
	printf("%s\n", b);
	printf("[%s]\n", b);
	printf("%x\n", b);
	return ok;
}

惭愧，曾经三度学习C，三度放弃C。实在没学会。

C语言只看过从入门到放弃的教程

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