Part of code to solve the "Temperatures" puzzle from codinggame.com

temperatures.c

// https://www.codingame.com/training/easy/temperatures
// gcc -std=c99 -Wall -pedantic -o temperatures temperatures.c
// ./temperatures <<< $(cat input.txt)
//
// input.txt
// 9
// 7 22 -99 0 -1 35 -2 +7654 21

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXARRSIZE 257

// String to Signed Int.
// len is the length of the input string.
// Returns the number of ints in nums, and fills nums by reference.
int str2sint(char* input, int* nums);

int closest_to_zero(int* nums, int len);

int main(void) {

    // the number of temperatures to analyse
    int n;

    int closest;
    int nums_len; // Quantity of numbers parsed.

    // the n temperatures expressed as integers ranging from -273 to 5526
    char temps[MAXARRSIZE] = {'\0'};
    int nums[MAXARRSIZE] = {'\0'}; // temps converted to signed ints.

    scanf("%d", &n);
    fgetc(stdin); // Reads the newline?

    // the n temperatures expressed as integers ranging from -273 to 5526
    fgets(temps, MAXARRSIZE, stdin);

    nums_len = str2sint(temps, nums);

    closest = closest_to_zero(nums, nums_len);
    fprintf(stdout, "Closest: %d\n", closest);

    return 0;
}

int str2sint(char* input, int* nums) {

    short int minus, digit;
    int temp_num, i;

    minus = 0;
    digit = 0;
    temp_num = 0;
    i = 0;

    while (*input != '\0') {
        if (*input == '-') {
            minus = 1;
            input++;
        }

        while (*input >= '0' && *input <= '9') {
            digit = 1;
            temp_num += *input - '0';
            temp_num *= 10;
            input++;
        }

        if (digit == 1 && (*input < '0' || *input > '9')) {

            temp_num /= 10;

            if (minus == 1) {
                temp_num *= -1;
            }

            nums[i++] = temp_num;
            temp_num = 0;
            minus = 0;
            digit = 0;
        }

        input++;
    }

    return i;
}

int closest_to_zero(int* nums, int len) {

    int i;
    int closest = 0;
    int distance, temp_distance;

    short int positive, negative;

    positive = negative = 0;

    if (len == 0) {
        return 0;
    }

    for (i = 0; i < len; ++i) {

        if (*nums > 0) positive = 1;

        if (0 == i) {
            closest = *nums;
            distance = abs(0 - *nums);

            ++nums;
            continue; // Back to start of loop.
        }

        temp_distance = abs(0 - *nums);

        if (temp_distance < distance) {
            distance = temp_distance;
            closest = *nums;
        }

        ++nums;
    }

    // There were no positive numbers.
    if (positive == 0) {
        // Returns without inverting the sign.
        return closest;
    }

    // If there are -3 and 3 which are closest, return the positive one.
    if (closest < 0 && distance == abs(closest)) {
        closest *= -1;
    }

    return closest;
}