作业（第三周）

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第一题：

例1

/***************************************    功能：布尔类型使用举例  ***************************************/# include<iostream># include<iomanip>using namespace std;int main(){bool flag = true;cout <<flag<<endl;cout <<boolalpha<<flag<<endl;cout <<flag + 5<<endl;flag = 0;cout<<"执行语句 flag=0;后 flag 的值为:"<<boolalpha<<flag<<endl;flag = 0.0;cout<<"执行语句 flag=0.0;后 flag 的值为:"<<boolalpha<<flag<<endl;return 0;}

例2

/***************************************    功能:赋值表达式语句的使用  ***************************************/# include<iostream>using namespace std;int main(){int a, b, c, d;a = 4;b = a;a = 5;c = d =6;c *= a;d %= a + b;cout<<"a = "<<a<<endl<<"b = "<<b<<endl<<"c = "<<c<<endl<<"d = "<<d<<endl;return 0;}

例3

# include<iostream>using namespace std;int main(){short i, j, m, n;i = 1000;j = 1000;m = i + j;n = i * j;    cout<<"m = "<<m<<endl;cout<<"n = "<<n<<endl;return 0;}

例4

# include<iostream>using namespace std;int main(){int i = 6, j, k, temp;j = ++i;k = i++;++i = 1;cout<<"i = "<<i<<endl<<"j = "<<j<<endl<<"k = "<<k<<endl;return 0;}

例5

# include<iostream>using namespace std;int main(){char ch;cout<<"please input a character:";cin>>ch;ch = ch>= 'a'&& ch<= 'z'? ch - 'a' + 'A' : ch;cout<<"The result is: "<<ch<<endl;return 0;}

例7

# include<iostream>using namespace std;int main(){int ab, ac;double b = 3.14;char c = 'A';ab = int(b);ac = int(c);cout<<"b = "<<b<<endl;cout<<"ab = "<<ab<<endl;cout<<"c = "<<c<<endl;cout<<"ac = "<<ac<<endl;return 0;}

第二题

三角形周长和面积

# include<iostream># include<math.h>using namespace std;int main(){int a, b, c;    cout<<"请输入三个数:";    cin>>a>>b>>c;    int p, d, s;    p = a + b + c;    d = p/2;    s = sqrt(d*(d-a)*(d-b)*(d-c));    cout<<"p = "<<p<<endl;    cout<<"s = "<<s<<endl;    return 0;}

第三题

（1）.

# include<iostream># include<math.h>using namespace std;int main(){int e=1, f=4, g=2;float m=10.5, n=4.0, k;k=(e+f)/g+sqrt((double)n)*1.2/g+m;cout<<"k= "<<k<<endl;return 0;}

k的运算顺序是先算括号中的e+f后再除以g，接着先运算（double）n之后再sqrt然后再乘以1.2接着除以g，再进行三个数的加法

（2）.

# include<iostream>using namespace std;int main(){float x=2.5, y=4.7, m;int a=7;m= x+a%3*(int(x+y)%2)/4;cout<<"m= "<<m<<endl;return 0;}

第四题

//          计算一元二次方程#include <iostream>#include <math.h>                        //函数调用using namespace std;int main(){    float a ,b ,c;    double anto ;    cout << "请输入二次项系数 a :";    cin >> a ;    cout << "请输入一次项系数 b :";    cin >> b ;    cout << "请输入常数项 c :";    cin >> c ;    if(a==0&&b==0)    {        cout << "该方程不是一元二次方程"<< endl;    }    anto = (b*b)-(4*a*c) ;     if (anto >= 0){        if (anto > 0){            cout << "方程的实数根 X1= " << (-b+sqrt(anto))/(2*a) << endl;            cout << " 方程的实数根X2= " << (-b-sqrt(anto))/(2*a) << endl;            }        else cout << "方程的实数根 X1 = X2 = " << (-b)/(2*a) << endl;    }    else {        anto=abs(anto);        cout << "方程的虚根X=" << -b/(2*a) <<"±"<<sqrt(anto)/(2*a) <<"j"<< endl;       }    return 0;}

博主太懒，很多知识点都还没学会，导致作业迟迟未能上交，如今还交了个半成品，望老师见谅，日后必补上。
第七题：

错误：warning C4305: 'initializing' : truncation from 'const double' to 'float'（第三题的第二个小题出现的错误，很是疑惑）

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