main(){ int a = –1, b = 4, k; k=(+ + a<0 )&& !(b––< 0) ; printf(“%d,%d,%d\n”,k,a,b) ; }

这段代码存在语法错误，无法编译通过。具体来说，变量a的赋值语句中使用了负号符号“-”和数字1，但是在这段代码中，这个符号被替换成了中文字符“-”，导致编译器无法识别，需要将其替换回正确的符号。同时，变量b的自减运算也存在错误，需要将其改为正确的自减运算“b--”。下面是修改后的代码：

main() {
    int a = -1, b = 4, k;
    k = (++a < 0) && !(b-- < 0);
    printf("%d,%d,%d\n", k, a, b);
}

这段代码的输出结果为“1,-1,3”。变量a的值在执行++a操作后变为了0，满足小于0的条件，因此表达式(++a<0)的值为1；变量b在执行b--操作后变为了3，不满足小于0的条件，因此表达式(b--<0)的值为0，再取反后为1；最后将这两个表达式进行逻辑与运算，结果为1。

相关问题

main( ) { int a = –1, b = 4, k; k=(+ + a<0 )&& !(b––< 0) ; printf(“%d,%d,%d\n”,k,a,b) ; } 三、程序填空题（本题共2小题，共6空，每空5分，共30分。） 1、已知圆的半径是10，编写程序求圆的面积。（π的值pi=3.1415） #define PI 3.1415 main() { int r=10; circle_area; circle_area= ; printf("圆的面积是 %.4f \n",circle_area); } 2、编写程序，判断所输入的数是奇数或是偶数，若是奇数，则输出“这是一个奇数”，否则，则输出“这是一个偶数”。 main() { int num; ; //输入语句，输入一个数num if( ) printf("这是一个偶数 \n"); else printf("这是一个奇数 \n"); } 3、任意输入一个字符，判断该字符是字符还是数字。 #include <stdio.h> int main() { char ch; ch=getchar(); if(ch>‘a') && (ch<=’u') ) ________①________ else ________②________ putchar(ch); }

1、已知圆的半径是10，编写程序求圆的面积。（π的值pi=3.1415）

#define PI 3.1415
main() {
    int r=10;
    float circle_area;
    circle_area= PI * r * r;
    printf("圆的面积是 %.4f \n",circle_area);
}

2、编写程序，判断所输入的数是奇数或是偶数，若是奇数，则输出“这是一个奇数”，否则，则输出“这是一个偶数”。

main() {
    int num;
    scanf("%d", &num);      //输入语句，输入一个数num
    if(num % 2 == 0) {
        printf("这是一个偶数 \n");
    } else {
        printf("这是一个奇数 \n");
    }
}

3、任意输入一个字符，判断该字符是字符还是数字。

#include <stdio.h>
int main() {
    char ch;
    ch = getchar();
    if(ch >= 'a' && ch <= 'z') {
        printf("这是一个字符 \n");
    } else if(ch >= '0' && ch <= '9') {
        printf("这是一个数字 \n");
    } else {
        printf("这不是一个字符也不是一个数字 \n");
    }
    putchar(ch);
}

C++Write a C++ program that defines a cmplx struct.The cmplx struct object type should include... Member Variables (public or private, you decide) two variables, each double as listed in the "Background" Public Members a default constructor – define all real and imaginary with zero cmplx() a user constructor – define all real and imaginary with user input, allow I=0 as default value cmplx(double, double=0) a copy constructor – define new unit object based on existing cmplx(const cmplx &) arithmetic operators – define four arithmetic operations for cmplx input + – * / arithmetic overload – define four arithmetic overloads for double input + – * / friend iostream directives – define input and output directives >> << friend arithmetic operator – define four friend operation for double + – * / friend square function – define math for square friend cmplx sq(cmplx &) friend cubic function – define math for cubic 。friend cmplx cu(cmplx &)

Here is a sample implementation of the cmplx struct in C++:

#include<iostream>
#include<cmath>

using namespace std;

struct cmplx {
private:
    double real;
    double imag;
public:
    cmplx(): real(0), imag(0) {}
    cmplx(double r, double i = 0): real(r), imag(i) {}
    cmplx(const cmplx& c): real(c.real), imag(c.imag) {}
    
    friend cmplx operator+(const cmplx& c1, const cmplx& c2) {
        return cmplx(c1.real + c2.real, c1.imag + c2.imag);
    }
    friend cmplx operator-(const cmplx& c1, const cmplx& c2) {
        return cmplx(c1.real - c2.real, c1.imag - c2.imag);
    }
    friend cmplx operator*(const cmplx& c1, const cmplx& c2) {
        return cmplx(c1.real*c2.real - c1.imag*c2.imag, c1.real*c2.imag + c1.imag*c2.real);
    }
    friend cmplx operator/(const cmplx& c1, const cmplx& c2) {
        double d = c2.real*c2.real + c2.imag*c2.imag;
        return cmplx((c1.real*c2.real + c1.imag*c2.imag) / d, (c1.imag*c2.real - c1.real*c2.imag) / d);
    }
    
    friend cmplx operator+(const cmplx& c, double d) {
        return cmplx(c.real + d, c.imag);
    }
    friend cmplx operator-(const cmplx& c, double d) {
        return cmplx(c.real - d, c.imag);
    }
    friend cmplx operator*(const cmplx& c, double d) {
        return cmplx(c.real*d, c.imag*d);
    }
    friend cmplx operator/(const cmplx& c, double d) {
        return cmplx(c.real/d, c.imag/d);
    }
    friend cmplx operator+(double d, const cmplx& c) {
        return c + d;
    }
    friend cmplx operator-(double d, const cmplx& c) {
        return cmplx(d) - c;
    }
    friend cmplx operator*(double d, const cmplx& c) {
        return c*d;
    }
    friend cmplx operator/(double d, const cmplx& c) {
        double d2 = c.real*c.real + c.imag*c.imag;
        return cmplx(d*c.real/d2, -d*c.imag/d2);
    }
    
    friend istream& operator>>(istream& is, cmplx& c) {
        is >> c.real >> c.imag;
        return is;
    }
    friend ostream& operator<<(ostream& os, const cmplx& c) {
        os << c.real << " + " << c.imag << "i";
        return os;
    }
    
    friend cmplx sq(cmplx& c) {
        return c*c;
    }
    friend cmplx cu(cmplx& c) {
        return c*c*c;
    }
};

int main() {
    cmplx a(1, 2), b(3, 4);
    cmplx c = a + b;
    cmplx d = a - b;
    cmplx e = a * b;
    cmplx f = a / b;
    cout << "a = " << a << endl;
    cout << "b = " << b << endl;
    cout << "a + b = " << c << endl;
    cout << "a - b = " << d << endl;
    cout << "a * b = " << e << endl;
    cout << "a / b = " << f << endl;
    cmplx g = a + 2.5;
    cmplx h = 3.7 - b;
    cmplx i = a * 1.5;
    cmplx j = b / 2.0;
    cout << "a + 2.5 = " << g << endl;
    cout << "3.7 - b = " << h << endl;
    cout << "a * 1.5 = " << i << endl;
    cout << "b / 2.0 = " << j << endl;
    cmplx k = 2.5 + a;
    cmplx l = 3.7 - b;
    cmplx m = 1.5 * a;
    cmplx n = 2.0 / b;
    cout << "2.5 + a = " << k << endl;
    cout << "3.7 - b = " << l << endl;
    cout << "1.5 * a = " << m << endl;
    cout << "2.0 / b = " << n << endl;
    cout << "a^2 = " << sq(a) << endl;
    cout << "b^3 = " << cu(b) << endl;
    return 0;
}

In this implementation, the cmplx struct has two private member variables for the real and imaginary parts. It also has a default constructor, a user constructor with a default value for the imaginary part, and a copy constructor. The struct defines arithmetic operators (+, -, *, /) for cmplx input and overloaded arithmetic operators for double input. It also defines input and output directives and friend math functions for square and cube.