统计数字字符的个数

#include<stdio.h>
int main(){
int count,i;
char str[80];
printf("Enter a string:");
i=0;
while((str[i]=getchar())!='\n'){
i++;
}
str[i]='\0';

count=0;
for(i=0;str[i]!='\0';i++){
if(str[i]<='9'&&str[i]>='0') count++;
}
printf("count=%d\n",count);
return 0;
}