Convert a String to Float

Code

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

float custom_atof(const char *str) {
    float result = 0.0, decimal = 1.0, sign = 1.0;
    bool comma = false;

    for(int i=0;str[i]!='\0';i++){
        if(str[i]>='0' && str[i]<='9'){
            result = result * 10 + (str[i]-'0');
            if(comma) decimal /=10.0;
        }
        else if(str[i] == '.') comma = true;
        else if(str[i] == '-') sign = -1.0;
    }
    return (result *= decimal)*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++;
    }

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

Solving Approach

 

 

 

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Input

123.45

Expected Output

123.45