Added atof

src/string.c

@@ -108,3 +108,51 @@ int stoi(char *str)
  
     return sign*res;
 }
+double atof(char* num)
+{
+    if (!num || !*num)
+	return 0; 
+    double integerPart = 0;
+    double fractionPart = 0;
+    int divisorForFraction = 1;
+    int sign = 1;
+    bool inFraction = false;
+    
+    if (*num == '-')
+    {
+	++num;
+	sign = -1;
+    }
+    else if (*num == '+')
+    {
+	++num;
+    }
+    while (*num != '\0')
+    {
+	if (*num >= '0' && *num <= '9')
+	{
+	    if (inFraction)
+            {
+		fractionPart = fractionPart*10 + (*num - '0');
+		divisorForFraction *= 10;
+	    }
+	    else
+            {
+		integerPart = integerPart*10 + (*num - '0');
+	    }
+	}
+	else if (*num == '.')
+	{
+	    if (inFraction)
+		return sign * (integerPart + fractionPart/divisorForFraction);
+	    else
+		inFraction = true;
+	}
+	else
+        {
+	    return sign * (integerPart + fractionPart/divisorForFraction);
+	}
+	++num;
+    }
+    return sign * (integerPart + fractionPart/divisorForFraction);
+ }

src/string.h

@@ -9,4 +9,5 @@ int strcmp(const char* s1, const char* s2);
 int strncmp(const char* s1, const char* s2, size_t n);
 int atoi(char *p);
 int stoi(char* str);
+double atof(char* num);
 #endif