iOS开发实现计算器功能

本文实例为大家分享了ios实现计算器功能的具体代码，供大家参考，具体内容如下

效果图

masonry

使用数组来自动约束

nsarray *buttonarrayone = @[_buttonac, _buttonleftbracket, _buttonrightbracket, _buttondivide];
    //withfixedspacing: 每个view中间的间距
    //leadspacing: 左最开始的间距
    //tailspacing:; 右边最后的的间距
    [buttonarrayone mas_distributeviewsalongaxis:masaxistypehorizontal withfixedspacing:15 leadspacing:15 tailspacing:15];
    [buttonarrayone mas_makeconstraints:^(masconstraintmaker *make) {
        make.top.equalto(@(selfheight - (buttonheight * 5 + 110)));
        make.height.equalto(@(buttonheight));
    }];

对最后一行单独处理

 [_buttonzero mas_makeconstraints:^(masconstraintmaker *make) {
        make.left.equalto(@15);
        make.top.equalto(@(selfheight - (buttonheight + 50)));
        make.width.equalto(@(buttonwidth * 2 + 15));
        make.height.equalto(@(buttonheight));
    }];
    
    [_buttonzero.titlelabel mas_makeconstraints:^(masconstraintmaker *make) {
        make.left.equalto(_buttonone.titlelabel);
    }];
    //使0的数字对齐

计算部分：

+ (result)calculatefor:(char*) formula andlen: (long) length {
    result result = {0, 0.0f};
    int numberofdots = 0;
    int index;
    int digitsnum = 0;
    float digits[calculate_max_digits];
    memset(digits, 0, sizeof(digits));
    int optnum = 0;
    char operator[calculate_max_operator];
    memset(operator, 0, sizeof(operator));
    int digitnum = 0;
    char digit[calculate_max_digit];
    memset(digit, 0, sizeof(digit));
    char *p = formula;
    while (length--) {
        switch (*p) {
            case '+':
            case '-':
            case '*':
            case '/':
                numberofdots = 0;
                if (0 == digitnum && '-' == *p) {
                    digit[digitnum++] = *p;
                } else {
                    if (-1 == digitnum) {
                        //刚计算过括号，符号前可以没有数字读入
                    } else if (0 == digitnum || calculate_max_digits == digitsnum - 1) {
                        result.error = calculate_err;
                        return result;
                    } else {
                        digits[digitsnum++] = atof(digit);
                        memset(digit, '\0', sizeof(digit));
                    }
                    digitnum = 0;
                    operator[optnum++] = *p;
                }
                break;

            case '(': {
                char *pointer_son;
                int existend = 0;
                pointer_son = ++p;
                while(length--) {
                    if ('(' == *p) {
                        existend--;
                    } else if (')' == *p) {
                        existend++;
                    }
                    if (1 == existend) {
                        break;
                    }
                    p++;
                }
                result result_son = [self calculatefor:pointer_son andlen:p - pointer_son];
                if (calculate_err == result_son.error) {
                    result.error = result_son.error;
                    return result;
                }
                digits[digitsnum++] = result_son.value;
                memset(digit, 0, sizeof(digit));
                digitnum = -1;
                break;
            }
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
            case '8':
            case '9':
            case '.':
                digit[digitnum++] = *p;
                if (numberofdots == 0 && *p == '.') {
                    numberofdots = 1;
                } else if (numberofdots == 1 && *p == '.') {
                    result.error = calculate_err;
                    return result;
                }
                break;

            default:
                result.error = calculate_err;
                return result;

        }
        if (0 == length && 0 < digitnum) {
            digits[digitsnum++] = atof(digit);
            memset(digit, 0, sizeof(digit));
            digitnum = 0;
        }
        p ++;
    }
    if (digitsnum != optnum + 1) {
        result.error = calculate_err;
        return result;
    }
    for (index = 0; index < optnum; index ++) {
        if ('*' == operator[index]) {
            digits[index + 1] = digits[index] * digits[index + 1];
            digits[index] = 0;
            operator[index] = '?';
        } else if ('/' == operator[index]) {
            if (digits[index + 1] == 0) {
                result.error = calculate_err;
                return result;
            }
            digits[index + 1] = digits[index] / digits[index + 1];
            digits[index] = 0;
            operator[index] = '?';
        }
    }
    for (index = 0; index < optnum; index ++) {
        if ('?' == operator[index]) {
            if (0 == index) {
                operator[index] = '+';
            } else {
                operator[index] = operator[index - 1];
            }
        }
    }
    result.value = digits[0];
    for (index = 0; index < optnum; index ++) {
        if ('+' == operator[index]) {
            result.value += digits[index + 1];
        } else if ('-' == operator[index]) {
            result.value -= digits[index + 1];
        }
    }
    return result;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。