通过C语言判断字符串是否为点分十进制的IP地址

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define maxsize 100
//十进制转为十六进制
int dtox(int n,char st[]){
	int m;
	int top=-1;
	char c[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
	while(n){
		m=n%16;
		st[++top]=c[m];
		n=n/16;
	}
	return top;
}
//输出十进制转为十六进制的结果
void out(char st[],int top){
	while(top>-1){
		printf("%c",st[top--]);
	}
}
//将十进制的192字符串转为int类型的192
int stringtoint(char s[]){
	int sum=0;
	int count=1;
	for(int i=strlen(s)-1;i>=0;i--){
		sum+=(s[i]-'0')*count;
		count=count*10;		
	}
	return sum;
}
//将字符串用.分开
int split(char s[],int t[])
{	char tmp[maxsize];
	memset(tmp, 0, sizeof(tmp));
	int count,c;
	int n1=0;
	int i=0;
	int n;
	c=0;
	while(i<strlen(s)){
		count=0;
		while(s[i]!='\0'&&s[i]!='.'){
			if(s[i]>='0'&&s[i]<='9'){
				tmp[count++]=s[i++];
			}
			else return -1;
		}
		n=stringtoint(tmp);
		if(n>255 or n<0) return -1;

		t[n1++]=n;
		memset(tmp, 0, sizeof(tmp));
		i++; 
	}
	return n1;
}
//判断是否是正确的十进制ip地址
void panduan(){
	char s[maxsize];
	scanf("%s",s);
//	char s[]="192.41.6.20";
//	char s[]="abc.41.6.20";
//  192.41.6.20.22
	int t[maxsize];
	int n1;
	n1=split(s,t);
	if(n1>4||n1==-1){
		printf("error"); 
		return ;
	} 
	for(int i=0;i<n1;i++){
		if(i==0)	printf("%#02X",t[i]); 
		else printf("%02X",t[i]);
	}
}
int main(){
	panduan();
//验证十六进制转为十进制的函数 
//	int n;
//	scanf("%d",&n);
//	char st[maxsize];
//	int top;
//	top=dtox(n,st);
//	out(st,top);
//验证十进制的字符串转为十进制数int类型 
//	char s[]="192";
//	printf("\n%d ",	stringtoint(s));
// "192.41.6.20"转为十六进制0XC0290614 
	
}

printf("%x\n", 47);  //输出结果为:    2f
printf("%X\n", 47);  //输出结果为:    2F
printf("%#x\n", 47); //输出结果为:    0x2f
printf("%#X\n",47); //输出结果为:    0X2F    %#X推荐使用

#include <stdio.h>
int main(){
    int a = 120;
	
    printf("%d\n",a);
    
    printf("%4d\n",a);
    
    printf("%04d\n",a);

	    
    printf("%x\n",a);
     
    printf("%4x\n",a);
    
    printf("%04x\n",a);

    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define maxsize 100
//十进制转为十六进制
int dtox(int n,char st[]){
	int m;
	int top=-1;
	char c[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
	while(n){
		m=n%16;
		st[++top]=c[m];
		n=n/16;
	}
	return top;
}
//输出十进制转为十六进制的结果
void out(char st[],int top){
	while(top>-1){
		printf("%c",st[top--]);
	}
}
int main(){
//验证十六进制转为十进制的函数 
	int n;
	scanf("%d",&n);
	char st[maxsize];
	int top;
	top=dtox(n,st);
	out(st,top);
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define maxsize 100
int stringtoint(char s[]){
	int sum=0;
	int count=1;
	for(int i=strlen(s)-1;i>=0;i--){
		sum+=(s[i]-'0')*count;
		count=count*10;		
	}
	return sum;
}
int main(){
	char s[]="192";
	printf("\n%d ",	stringtoint(s));
	}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define maxsize 100
void split(char s[])
{	char tmp[maxsize];
	memset(tmp, 0, sizeof(tmp));
	int count,c;
	int i=0;
	c=0;
	while(i<strlen(s)){
		count=0;
		while(s[i]!='\0'&&s[i]!='.'){
			tmp[count++]=s[i++];
//			printf("%c",tmp[count-1]);
		}
		printf("%s\n",tmp);
		memset(tmp, 0, sizeof(tmp));
		i++; 
	}
}
int main(){
	char s[]="192.23.32";
	split(s);
}