Convert String to Integer

Code

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

int custom_atoi(const char *str) {
    int res=0,f=1;
    for(int i=0;str[i];i++){
        if(i==0 && (str[i]=='-'||str[i]=='+')){
            f=(str[i]=='-')?-1:1;
        }
       else if(str[i]>='0'&&str[i]<='9'){
            res=res*10+(str[i]-'0');
        }else break;
    }
    return f*res;
}

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