如何将数组中的第一个元素分配给变量？

Question

I'm new to c and I have trouble with arrays in c. I don't know how to assign first element from an array to an int variable. When I tried, I got a random large integer from nowhere even index was in range.

This is part of my code:

int solve(int *elev, int n)
{
    for (int i = 0; i < n; ++i)
        printf("%d ", elev[i]);
    putchar('\n');

    printf("%d %d %d %d %d\n", elev[0], elev[1], elev[2], elev[3], elev[4]);

    int low = elev[0];
    int high = elev[4];

    printf("low:%d high:%d\n");

    // ...
}

Partial output:

1 4 20 21 24
1 4 20 21 24
low: 362452 high: 7897346

What was a cause of above output?

Answer 1

It looks like you're not passing the low or high variables as arguments to the printf() call, on this line:

printf("low:%d high:%d\\n")

If you provide the low and high variables as arguments to printf() then the expected output should be printed to the console, like so:

printf("low:%d high:%d\n", low, high);

The "print format" of "low:%d high:%d\\n" being passed to the printf() function states that number values will be displayed for each occurrence of %d in the format string.

In order to specify the actual values that will be displayed for each occurrence of %d , additional arguments must be provided to the printf() function - one for each occurrence of %d :

printf("low:%d high:%d\n", 
low, /* <- the value of low will be printed after "low:" in output the string */
high /* <- the value of low will be printed after "low:" in output the string */
);

If these additional arguments are not provided, the program will still compile and run however, at run-time, the program will basically display what ever value is found at the memory locations where it expected to find values for each of the %d occurrences.

For more information on printf() , you might like to see this documentation - hope this helps!