>>183
#include<stdio.h>
#define isnum(c) ('0'<=c && c<= '9')
int check(char *s){
int i = 0, f = 1;
if(*s == '0'){
while(*s && *++s == '0');
return !*s;
}else{
while(isnum(*s)){
while(*s && isnum(*s)){ i++; s++; }
if(i>3) return 0;
if(!*s && (f || i == 3)) return 1;
if(*s == ','){ i = f = 0; s++; }
}
return 0;
}
}
int main(){
char s[256];
while(1){
printf("入力数値：");
gets(s);
printf("判定結果：%s\n\n",check(s)?"有効":"無効");
}
}
途中であきらめた