Convert String to Integer

Code

#include <stdio.h>
#include <stdint.h>

int custom_atoi(const char *str) {
    // Your logic here
    int sign = 1;
    int res = 0;
    uint8_t i = 0;

    while (str[i] == ' ' || str[i] == '\t')
    {
        i++;
    }

    if (str[i] == '-')
    {
        sign = -1;
        i++;
    }else if (str[i] == '+')
    {
        i++;
    }

    uint8_t found_digit = 0;
    while (str[i] >= '0' && str[i] <= '9')
    {
        found_digit = 1;
        res = res * 10 + (str[i] - '0');
        i++;
    }
    if (!found_digit)
        return 0;

     return res * sign;
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    printf("%d", custom_atoi(str));
    return 0;
}

Solving Approach

 

 

 

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Input

123abc

Expected Output

123