iOS 字符串公式的计算（＋，－，＊，／，（），sin，cos，tan）

开卷友谊！！！！

今天发表我的第一篇博客对如下字符串公式的计算

该博文在博主http://blog.sina.com.cn/u/1958357554的基础上添加了三角函数

例如字符串str=@"2*sin(90/3)+5+cos(5*10+10)+10+tan(15*3)"

result=17.50

进入主题：.h

#import <UIKit/UIKit.h>

#import <Foundation/Foundation.h>

@interface ViewController : UIViewController

+ (NSString *)calcComplexFormulaString:(NSString *)formula;

@end

.m

#import "ViewController.h"

#import <math.h>

@interface ViewController ()

{

UITextField *_textField;

}

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

_textField=[[UITextField alloc]initWithFrame:CGRectMake(30, 50, 300, 50)];

_textField.backgroundColor=[UIColor yellowColor];

_textField.text=@"2*sin(30)+5+cos(30)+tan(30)";

[self.view addSubview:_textField];

UIButton *button=[[UIButton alloc]initWithFrame:CGRectMake(20, 100, 50, 50)];

button.backgroundColor=[UIColor redColor];

[button addTarget:self action:@selector(click) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button];

}

-(void)click

{

NSString *result = [ViewController calcComplexFormulaString:_textField.text];

NSLog(@"result=%@",result);

}

// 字符串加

+ (NSString *)addV1:(NSString *)v1 v2:(NSString *)v2 {

CGFloat result = [v1 floatValue] + [v2 floatValue];

return [NSString stringWithFormat:@"%.2f", result];

}

// 字符串减

+ (NSString *)subV1:(NSString *)v1 v2:(NSString *)v2 {

CGFloat result = [v1 floatValue] - [v2 floatValue];

return [NSString stringWithFormat:@"%.2f", result];

}

// 字符串乘

+ (NSString *)mulV1:(NSString *)v1 v2:(NSString *)v2 {

CGFloat result = [v1 floatValue] * [v2 floatValue];

return [NSString stringWithFormat:@"%.2f", result];

}

// 字符串除

+ (NSString *)divV1:(NSString *)v1 v2:(NSString *)v2 {

CGFloat result = [v1 floatValue] / [v2 floatValue];

return [NSString stringWithFormat:@"%.2f", result];

}

// 字符串sin

+ (NSString *)sinV1:(NSString *)v1 {

NSLog(@"v1 %0.4f",v1.floatValue);

double result =sin([v1 floatValue]*M_PI/180.0);

return [NSString stringWithFormat:@"%.4f", result];

}

// 字符串cos

+ (NSString *)cosV1:(NSString *)v1 {

NSLog(@"v1 %0.4f",v1.floatValue);

double result =cos([v1 floatValue]*M_PI/180.0);

return [NSString stringWithFormat:@"%.4f", result];

}

// 字符串tan

+ (NSString *)tanV1:(NSString *)v1 {

NSLog(@"v1 %0.4f",v1.floatValue);

double result =tan([v1 floatValue]*M_PI/180.0);

return [NSString stringWithFormat:@"%.4f", result];

}

// 简单只包含 + - 的计算

+ (NSString *)calcSimpleFormula:(NSString *)formula {

NSString *result = @"0";

char symbol = '+';

int len = (int)formula.length;

int numStartPoint = 0;

for (int i = 0; i < len; i++) {

char c = [formula characterAtIndex:i];

if (c == '+' || c == '-') {

NSString *num = [formula substringWithRange:NSMakeRange(numStartPoint, i - numStartPoint)];

switch (symbol) {

case '+':

result = [self addV1:result v2:num];

break;

case '-':

result = [self subV1:result v2:num];

break;

default:

break;

}

symbol = c;

numStartPoint = i + 1;

}

}

if (numStartPoint < len) {

NSString *num = [formula substringWithRange:NSMakeRange(numStartPoint, len - numStartPoint)];

switch (symbol) {

case '+':

result = [self addV1:result v2:num];

break;

case '-':

result = [self subV1:result v2:num];

break;

default:

break;

}

}

return result;

}

// 获取字符串中的前置数字

+ (NSString *)firstNumberWithString:(NSString *)str {

int numEndPoint = (int)str.length;

for (int i = 0; i < str.length; i++) {

char c = [str characterAtIndex:i];

if ((c < '0' || c > '9') && c != '.') {

numEndPoint = i;

break;

}

}

return [str substringToIndex:numEndPoint];

}

// 获取字符串中的后置数字

+ (NSString *)lastNumberWithString:(NSString *)str {

int numStartPoint = 0;

for (int i =(int)str.length-1; i >= 0; i--) {

char c = [str characterAtIndex:i];

if ((c < '0' || c > '9') && c != '.') {

numStartPoint = i + 1;

break;

}

}

return [str substringFromIndex:numStartPoint];

}

// 包含 * / 的计算

+ (NSString *)calcNormalFormula:(NSString *)formula {

NSRange mulRange = [formula rangeOfString:@"*" options:NSLiteralSearch];

NSRange divRange = [formula rangeOfString:@"/" options:NSLiteralSearch];

// 只包含加减的运算

if (mulRange.length == 0 && divRange.length == 0) {

return [self calcSimpleFormula:formula];

}

// 进行乘除运算

int index = (int)mulRange.length > 0 ? (int) mulRange.location : (int)divRange.location;

// 计算左边表达式

NSString *left = [formula substringWithRange:NSMakeRange(0, index)];

NSString *num1 = [self lastNumberWithString:left];

left = [left substringWithRange:NSMakeRange(0, left.length - num1.length)];

// 计算右边表达式

NSString *right = [formula substringFromIndex:index + 1];

NSString *num2 = [self firstNumberWithString:right];

right = [right substringFromIndex:num2.length];

// 计算一次乘除结果

NSString *tempResult = @"0";

if (index == mulRange.location) {

tempResult = [self mulV1:num1 v2:num2];

} else if(index == divRange.location) {

tempResult = [self divV1:num1 v2:num2];

}

// 代入计算得到新的公式

NSString *newFormula = [NSString stringWithFormat:@"%@%@%@", left, tempResult, right];

return [self calcNormalFormula:newFormula];

}

// 三角函数计算公式计算,接口主方法

+ (NSString *)calcSanJiaoFormulaString:(NSString *)formula

{

NSRange sinRange = [formula rangeOfString:@"sin" options:NSLiteralSearch];

NSRange cosRange = [formula rangeOfString:@"cos" options:NSLiteralSearch];

NSRange tanRange = [formula rangeOfString:@"tan" options:NSLiteralSearch];

if (sinRange.length==0&&cosRange.length==0&&tanRange.length==0) {

return [self calcNormalFormula:formula];

}

else if (sinRange.length==3) {

// 获取sin左边的表达式

NSString *left1 = [formula substringWithRange:NSMakeRange(0, sinRange.location)];

// 获取sin括号右边的表达式

NSString *right1 = [formula substringFromIndex:sinRange.location+3];

NSString *right2 =[formula substringFromIndex:sinRange.location+8];

NSString *tempResult;

tempResult = [self sinV1:right1];

formula = [NSString stringWithFormat:@"%@%@%@", left1, [self calcNormalFormula:tempResult],right2];

}

else if (cosRange.length==3) {

// 获取sin左边的表达式

NSString *left1 = [formula substringWithRange:NSMakeRange(0, cosRange.location)];

// 获取sin括号右边的表达式

NSString *right1 = [formula substringFromIndex:cosRange.location+3];

NSString *right2 =[formula substringFromIndex:cosRange.location+8];

NSString *tempResult;

tempResult = [self cosV1:right1];

formula = [NSString stringWithFormat:@"%@%@%@", left1, [self calcNormalFormula:tempResult],right2];

}

else if (tanRange.length==3) {

// 获取sin左边的表达式

NSString *left1 = [formula substringWithRange:NSMakeRange(0, tanRange.location)];

// 获取sin括号右边的表达式

NSString *right1 = [formula substringFromIndex:tanRange.location+3];

NSString *right2 =[formula substringFromIndex:tanRange.location+8];

NSString *tempResult;

tempResult = [self tanV1:right1];

formula = [NSString stringWithFormat:@"%@%@%@", left1, [self calcNormalFormula:tempResult],right2];

}

return [self calcSanJiaoFormulaString:formula];

}

// 复杂计算公式计算,接口主方法

+ (NSString *)calcComplexFormulaString:(NSString *)formula {

// 左括号

NSRange lRange = [formula rangeOfString:@"(" options:NSBackwardsSearch];

if (lRange.length == 0) {

return [self calcSanJiaoFormulaString:formula];

}

// 右括号

NSRange rRange = [formula rangeOfString:@")" options:NSLiteralSearch range:NSMakeRange(lRange.location, formula.length-lRange.location)];

// 获取括号左右边的表达式

NSString *left = [formula substringWithRange:NSMakeRange(0, lRange.location)];

NSString *right = [formula substringFromIndex:rRange.location + 1];

// 括号内的表达式

NSString *middle = [formula substringWithRange:NSMakeRange(lRange.location+1, rRange.location-lRange.location-1)];

// 代入计算新的公式

NSString *newFormula = [NSString stringWithFormat:@"%@%@%@", left, [self calcNormalFormula:middle], right];

return [self calcComplexFormulaString:newFormula];

}

结束战斗！复制即可用！再次感谢http://blog.sina.com.cn/u/1958357554博主的启发引导，如果有用随便拿走