#include <stdio.h>
#include <stdint.h>
float custom_atof(const char *s) {
float reg=0.0f;
float dau=1.0f;
int i=0;
if(s[i]=='+'){
dau=1.0f;
i++;
}
else if(s[i]=='-'){
dau=-1.0f;
i++;
}
while(s[i]>='0' && s[i]<='9'){
reg=reg*10.0f+(s[i]-'0');
i++;
}
float chia=10.0f;
if(s[i]=='.'){
i++;
while(s[i]>='0' && s[i]<='9'){
reg=reg+(s[i]-'0')/chia;
chia=chia*10.0f;
i++;
}
}
return reg*dau;
}
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;
}
Input
123.45
Expected Output
123.45