Finding largest and smallest numbers using atoi

Question

    scanf("%1c%2c %d %d %d %d %d %d %d %d %d %d",
          &x, &y, &arr[0], &arr[1], &arr[2], &arr[3], &arr[4],
          &arr[5], &arr[6], &arr[7], &arr[8], &arr[9]);
    strcpy(string, x);
    value1 = atoi(string);

    strcpy(string, y);
    value2 = atoi(string);

    value_final = value1 + value2;

I'm trying to get the ascii values for the -l or -s then pass them through the switch with the ascii values added but I'm getting errors when I use atoi and I'm not sure as to if you are supposed to be adding the ascii values when the user enters the -l or -s or if their is another way to do this?

Answer 1

Your code has several problems:

• Major: the switch cases do not have a break; clause. Control falls into the next clause and finally into the default statement.
• Major: your show confusion between char arrays and single char variables: strcpy(string, x); should not even compile.
• Your method for parsing -l or -s is very convoluted and probably erroneous. You should use character literals.
• You do not need a double loop to find the smallest or the largest element in an array. A single loop suffices, and the printf statement should be outside the loop. max and min are uninitialized, the loops invoke undefined behavior.
• the title says using atoi() : if this was your assignment, you should not use scanf() .

Here is a simplified version:

int main(void) {
    char option[3], buffer[32];
    int i, min, max, value;

    min = max = 0;
    if (scanf("%2s", option) == 1) {
        for (int i = 0; i < 10 && scanf("%31s", buffer) == 1; i++) {
            value = atoi(buffer);
            if (i == 0) {
                min = max = value;
            } else {
                if (min > value)
                    min = value;
                if (max < value)
                    max = value;
            }
        }
        if (!strcmp(option, "-l")) {
            printf("output: The largest number is %d\n", max);
            return 0;
        } else
        if (!strcmp(option, "-s")) {
            printf("output: The smallest number is %d\n", min);
            return 0;
        }
    }
    printf("You have entered an invalid option, try again next time.\n");
    return 0;
}