7-12

#include<stdio.h>
int main(void)
{
int i,number;
char str[10];

printf("Enter a string:");
i=0;
while((str[i]=getchar( ))!='\n')
i++;
str[i]='\0';

number=0;
for(i=0;str[i]!='\0';i++)
if(str[i]>='0'&& str[i]<='9')
number=number*10+str[i]-'0';

printf("digit=%d\n",number);

return 0;
}