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;
}