Convert String to Integer

Code

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

int custom_atoi(const char *str) {
    // Your logic here
    int num = 0, i = 0;
    while(str[i]!='\0'){
        if(((int)str[i] >= 65 && (int)str[i] <= 90) || ((int)str[i] >= 97 && (int)str[i] <= 122)){
            break;
        }
        if((int)str[i] >= 48 && (int)str[i] <= 57){
            num = num * 10 + (str[i] - '0');
        }
        if(str[i]==45){
            ++i;
            while((int)str[i] >= 48 && (int)str[i] <= 57){
            num = num * 10 + (str[i] - '0');
            i++;
            }
            num = num * -1;
            return num;
        }
        i++;
    }
    return num;
}

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