第1讲 变量、输入输出、表达式与顺序语句

1. A + B

#include 

using namespace std;

int main()
{
    int a, b;
    cin >> a >> b;
    
    cout << a + b << endl;
    
    return 0;
}

604. 圆的面积

#include 

const double pi = 3.14159;

int main ()
{
    double r;
    scanf("%lf", &r);
    
    printf("A=%.4lfn", pi * r * r);
    
    return 0;
}

• 浮点数一般用double(精度问题)
• 保留几位小数的时候一般用 scanf / printf 进行输入输出

605. 简单乘积

#include 

using namespace std;

int main()
{
    int a, b;
    cin >> a >> b;
    
    cout << "PROD = " << a * b << endl;
    
    return 0;
}

606. 平均数1

#include 

int main ()
{
    double a, b;
    scanf("%lf%lf", &a, &b);
    
    printf("MEDIA = %.5lfn", (a * 3.5 + b * 7.5) / 11);
    
    return 0;
}

607. 平均数2

#include 
#include 

using namespace std;

int main()
{
    double a, b, c;
    cin >> a >> b >> c;
    
    printf("MEDIA = %.1lfn", a * 0.2 + b * 0.3 + c * 0.5);
    
    return 0;
}

608. 差

#include 

using namespace std;

int main()
{
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    
    cout << "DIFERENCA = " << a * b - c * d << endl;
    
    return 0;
}

609. 工资

#include 

int main()
{
    int number, hour;
    double money;
    scanf("%d%d%lf", &number, &hour, &money);
    
    printf("NUMBER = %dnSALARY = U$ %.2lfn", number, money * hour);
    
    return 0;
}

610. 工资和奖金

#include 
#include 

using namespace std;

int main()
{
    string name;
    double x, y;
    cin >> name >> x >> y;
    
    printf("TOTAL = R$ %.2lfn", x + 0.15 * y);
    
    return 0;
}

611. 简单计算

#include 
#include 

using namespace std;

int main()
{
    int n1, n2, s1, s2;
    double p1, p2;
    cin >> n1 >> s1 >> p1;
    cin >> n2 >> s2 >> p2;
    
    printf("VALOR A PAGAR: R$ %.2lfn", s1 * p1 + s2 * p2);
    
    return 0;
}

612. 球的体积

#include 

const double pi = 3.14159;

int main()
{
    int r;
    scanf("%d", &r);
    
    printf("VOLUME = %.3lfn", 4 / (3.0) * pi * r * r * r);
    
    return 0;
}

613. 面积

#include 

const double pi = 3.14159;

int main()
{
    double a, b, c;
    scanf("%lf%lf%lf", &a, &b, &c);
    
    printf("TRIANGULO: %.3lfn", a * c / 2);
    printf("CIRCULO: %.3lfn", pi * c * c);
    printf("TRAPEZIO: %.3lfn", (a + b) * c / 2);
    printf("QUADRADO: %.3lfn", b * b);
    printf("RETANGULO: %.3lfn", a * b);
    
    return 0;
}

614. 最大值

#include 

using namespace std;

int main ()
{
    int a, b, c, maxnum;
    cin >> a >> b >> c;
    
    maxnum = (a + b + abs(a - b)) / 2;
    maxnum = (maxnum + c + abs(maxnum - c)) / 2;
    
    cout << maxnum << " eh o maior" << endl;
    
    return 0;
}

max = (a + b + abs(a - b)) / 2;

615. 油耗

#include 

int main()
{
    int s;
    double oil;
    scanf("%d %lf", &s, &oil);
    
    printf("%.3lf km/ln", s / oil);
    
    return 0;
}

616. 两点间的距离

#include 
#include 

int main()
{
    double x1, y1, x2, y2;
    scanf("%lf%lf", &x1, &y1);
    scanf("%lf%lf", &x2, &y2);
    
    printf("%.4lfn", sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)));
    
    return 0;
}

617. 距离

#include 

using namespace std;

int main ()
{
    int s;
    cin >> s;
    
    cout << s * 2 << " minutos" << endl;
    
    return 0;
}

618. 燃料消耗

#include 

int main()
{
    long long s, t;
    scanf("%lld %lld", &s, &t);
    
    printf("%.3lf",s * t / 12.0);
    
    return 0;
}

// 数据范围(10^18)超过 int(2*10^9)

数据范围10¹⁸ int - 2*10⁹

653. 钞票

#include 

using namespace std;

int main()
{
    int money;
    int cash[] = {100, 50, 20, 10, 5, 2, 1};
    cin >> money;
    
    cout << money << endl;;
    for(int i = 0; i < 7; i ++ )
    {
        cout << money / cash[i] << " nota(s) de R$ " << cash[i] << ",00" << endl;
        money -= (money / cash[i]) * cash[i];
    }
    
    return 0;
}

654. 时间转换

#include 

using namespace std;

int main()
{
    int n;
    cin >> n;
    
    cout << n / 3600 << ":" << n % 3600 / 60 << ":" << n % 60 << endl;
    
    return 0;
}

655. 天数转换

#include 

using namespace std;

int main()
{
    int n;
    cin >> n;
    
    cout << n / 365 << " ano(s)" << endl;
    cout << n % 365 / 30 << " mes(es)" << endl;
    cout << n % 365 % 30 << " dia(s)" << endl;
    
    return 0;
}

656. 钞票和硬币

#include 

int main()
{
    int a[] = {100, 50, 20, 10, 5, 2};
    int b[] = {100, 50, 25, 10, 5, 1};
    double money;
    scanf("%lf", &money);
	
    int n = money * 100;
    
    printf("NOTAS:n");
    for(int i = 0; i < 6; i ++ )
    {
        printf("%d nota(s) de R$ %.2lfn", n / (a[i] * 100), (double)a[i]);
        n -= n / (a[i] * 100) * (a[i] * 100);
    }
    
    printf("MOEDAS:n");
    for(int i = 0; i < 6; i ++ )
    {
        printf("%d moeda(s) de R$ %.2lfn", n / b[i], b[i] / 100.0);
        n -= n / b[i] * b[i];
    }
    return 0;
}

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其他知识点

变量类型	变量取值	变量空间	输入输出类型
bool	false / true	1B
char	‘a’	1B	%c
int	-231 ~ 231-1	4B	%d
long long	-263 ~ 263-1	8B	%lld
float	6~7 位有效数字	4B	%f
double	15~16 位有效数字	8B	%lf
long double	18~19 位有效数字	16B	%llf