Convert String to Integer

Code

#include <stdio.h>
#include <stdint.h>
int is_digit(char ch){
    if((ch>='0')&&(ch<='9')) return 1;
    return 0;
}
int custom_atoi(const char *str) {
    int i=0,sign=1,dec=0;
    while(str[i]==' ') i++;
    if((str[i]=='-')||(str[i]=='+')){
        if(str[i]=='-'){
            sign=-1;
        }
        i++;
    }
    while(is_digit(str[i])){
        dec=dec*10+(str[i]-'0');
        i++;
    }
    return dec*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