IP判断 （C语言代码）

解题思路:

注意事项:

参考代码:

# include<stdio.h>

# include<string.h> 

char a[4],b[4],c[4],d[4],ip[30];

int s1=0,s2=0,s3=0,s4=0;

void panduan(char *ip);

void fenduan();

int main(){

while(scanf("%s",ip)!=EOF){

panduan(ip);

}

return 0;

} 

void fenduan(){

int i=0;

int s1=0,s2=0,s3=0,s4=0;

while(ip[i]!='.'){

a[s1]=ip[i];

s1++;

i++;

}

i++;

while(ip[i]!='.'){

b[s2]=ip[i];

s2++;

i++;

}

i++;

while(ip[i]!='.'){

c[s3]=ip[i];

s3++;

i++;

}

i++;

while(i<strlen(ip)){

d[s1]=ip[i];

s4++;

i++;

}

}

void panduan(char *ip){

int s,j;

s=strlen(ip);

if(s>15){

printf("N\n");return ;

}

else{

fenduan();

int sum=0,sum1=0,sum2=0,sum3=0;

if(a[0]=='-' || b[0]=='-' || c[0]=='-' || d[0]=='-'){

printf("N\n");return ;

}

else{

for(j=0;j<=s1;j++){

if(a[j]>='0' && a[j]<='9')

sum=sum*10+(a[j]-'0');

else{

printf("N\n"); return ;

}

}

if(sum>255){

printf("N\n");return ;

}

for(j=0;j<=s2;j++){

if(b[j]>='0' && b[j]<='9')

sum1=sum1*10+(b[j]-'0');

else{

printf("N\n"); return ;

}

}

if(sum1>255){

printf("N\n");return ;

}

for(j=0;j<=s3;j++){

if(c[j]>='0' && c[j]<='9')

sum2=sum2*10+(c[j]-'0');

else{

printf("N\n"); return ;

}

}

if(sum2>255){

printf("N\n");return ;

}

for(j=0;j<=s4;j++){

if(d[j]>='0' && d[j]<='9')

sum3=sum3*10+(d[j]-'0');

else{

printf("N\n"); return ;

}

}

if(sum3>255){

printf("N\n");return ;

}

printf("Y\n");

}

}

}