var getCorrectResult = function(type, num1, num2, result) {
var temp_result = 0;
switch (type) {
case "add":
temp_result = num1 + num2;
break;
case "sub":
temp_result = num1 - num2;
break;
case "div":
temp_result = num1 / num2;
break;
case "mul":
temp_result = num1 * num2;
break;
}
if (Math.abs(result - temp_result) > 1) {
return temp_result;
}
return result;
};
var convertToInt = function(num) {
num = Number(num);
var newNum = num;
var times = countDecimals(num);
var temp_num = num.toString().toUpperCase();
if (temp_num.split('E').length === 2) {
newNum = Math.round(num * Math.pow(10, times));
} else {
newNum = Number(temp_num.replace(".", ""));
}
return newNum;
};
var countDecimals = function(num) {
var len = 0;
try {
num = Number(num);
var str = num.toString().toUpperCase();
if (str.split('E').length === 2) { // scientific notation
var isDecimal = false;
if (str.split('.').length === 2) {
str = str.split('.')[1];
if (parseInt(str.split('E')[0]) !== 0) {
isDecimal = true;
}
}
var x = str.split('E');
if (isDecimal) {
len = x[0].length;
}
len -= parseInt(x[1]);
} else if (str.split('.').length === 2) { // decimal
if (parseInt(str.split('.')[1]) !== 0) {
len = str.split('.')[1].length;
}
}
} catch(e) {
throw e;
} finally {
if (isNaN(len) || len < 0) {
len = 0;
}
return len;
}
};
//加法防止0.3显示为0.30000000000000004
var accAdd = function(num1, num2) {
num1 = Number(num1);
num2 = Number(num2);
var dec1, dec2, times;
try { dec1 = countDecimals(num1)+1; } catch (e) { dec1 = 0; }
try { dec2 = countDecimals(num2)+1; } catch (e) { dec2 = 0; }
times = Math.pow(10, Math.max(dec1, dec2));
// var result = (num1 * times + num2 * times) / times;
var result = (accMul(num1, times) + accMul(num2, times)) / times;
return getCorrectResult("add", num1, num2, result);
// return result;
};
//减法防止0.3显示为0.30000000000000004
var accSub = function(num1, num2) {
num1 = Number(num1);
num2 = Number(num2);
var dec1, dec2, times;
try { dec1 = countDecimals(num1)+1; } catch (e) { dec1 = 0; }
try { dec2 = countDecimals(num2)+1; } catch (e) { dec2 = 0; }
times = Math.pow(10, Math.max(dec1, dec2));
// var result = Number(((num1 * times - num2 * times) / times);
var result = Number((accMul(num1, times) - accMul(num2, times)) / times);
return getCorrectResult("sub", num1, num2, result);
// return result;
};
//÷法防止0.3显示为0.30000000000000004
var accDiv = function(num1, num2) {
num1 = Number(num1);
num2 = Number(num2);
var t1 = 0, t2 = 0, dec1, dec2;
try { t1 = countDecimals(num1); } catch (e) { }
try { t2 = countDecimals(num2); } catch (e) { }
dec1 = convertToInt(num1);
dec2 = convertToInt(num2);
var result = accMul((dec1 / dec2), Math.pow(10, t2 - t1));
return getCorrectResult("div", num1, num2, result);
// return result;
};
//陈法防止0.3显示为0.30000000000000004
var accMul = function(num1, num2) {
num1 = Number(num1);
num2 = Number(num2);
var times = 0, s1 = num1.toString(), s2 = num2.toString();
try { times += countDecimals(s1); } catch (e) { }
try { times += countDecimals(s2); } catch (e) { }
var result = convertToInt(s1) * convertToInt(s2) / Math.pow(10, times);
return getCorrectResult("mul", num1, num2, result);
// return result;
};
var num= accAdd(0.1,0.2);
//输出为0.3