Exercise 3-3 the last 3 bits of the product

Enter a number of integers (which can be positive, negative, or 0) to output the last 3 bits of their product. These integers are mixed with a string of uppercase letters, and your program should ignore them. Tip: Try to enter a string when executing scanf ("%d").

Problem Solving Ideas:
Find out the number multiplier in the string, note the end of the string in the calculation process and overflow the exception.

 #include <stdio.h> #include <string.h> #include <ctype.h> int main () {
    Char strarr[1000];
    scanf ("%[^\n]s", Strarr);
    int len = strlen (Strarr);
    int i;
    int flag = 1;
    int sum = 1;
    int ret = 1;
        for (i = 0; i < len; i++) {flag = 1;
        sum = 1;
        while (!isdigit (Strarr[i]) && strarr[i]! = '-' && strarr[i]! = ' \ n ') {i++;
        } if (strarr[i] = = '-') {flag =-flag;
            } if (IsDigit (Strarr[i])) {sum = strarr[i]-' 0 ';
            i++;
                while (IsDigit (Strarr[i])) {sum%= 1000;
                sum = sum * ten + strarr[i]-' 0 ';
            i++;
    }} RET = flag * Sum * ret% 1000;
    } printf ("%d\n", ret);  
return 0; }