Convert a String to Float

Code

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

float custom_atof(const char *str) {
   float res=0.0;
   float decimal=0.1;
   int i=0;
   int sign=1;
   while(str[i]==' '){
    i++;
   }
   if(str[i]=='+'|| str[i]=='-'){
    if(str[i]=='-')
    sign=-1;
    i++;
   }
   while(str[i]>='0'&& str[i]<='9'){
    res=res*10+(str[i]-'0');
    i++;
   }
   if(str[i]=='.'){
    i++;
    while(str[i]>='0'&&str[i]<='9'){
        res=res+(str[i]-'0')*decimal;
        decimal*=0.1;
        i++;
    }
   }
    return sign*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++;
    }

    float value = custom_atof(str);
    printf("%.2f", value);
    return 0;
}

Solving Approach