Computer programming test 1
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
cout << “Hello world”;
return 0;
}
int main()
{
int number1;
int number2;
int sum;
cout << “Enter first integer: ”;
cin >> number1;
cout << “Enter second integer: ”;
cin >> number2;
sum = number1 + number2;
cout << “Sum is “ << sum << endl;
}
int main()
{
int number1;
int number2;
cout << “Enter two integer to compare: “;
cin >> number1 >> number2;
if(number1 == number2)
cout << number1 << “==” << number2 << endl;
if(number1 != number2)
cout << number1 << “!=” << number2 << endl;
if(number1 < number2)
cout << number1 << “<” << number2 << endl;
if(number1 > number2)
cout << number1 << “>” << number2 << endl;
}
cout << ((grade >= 60) ? ”Passed” : “Failed“);
or
(grade >= 60 ? cout << ”Passed” : cout << “Failed“);
意思：
if ( grade >= 60 )
cout << "Passed";
else
cout << "Failed";
if ( studentGrade >= 90 ) // 90 and above gets "A"
cout << "A";
else if ( studentGrade >= 80 ) // 80-89 gets "B"
cout << "B";
else if ( studentGrade >= 70 ) // 70-79 gets "C"
cout << "C";
else if ( studentGrade >= 60 ) // 60-69 gets "D"
cout << "D";
else // less than 60 gets "F"
cout << "F";
if ( x > 5 )
{
if ( y > 5 )
cout << "x and y are > 5";
}
else
cout << "x is <= 5";
setprecision(2)
Rounded to 2 digits of precision to the right of the decimal point
(e.g., 92.37, 12345.78, 0.17)
Stream manipulator fixed: output in fixed-point format, as
opposed to scientific notation (scientific,e.g. 9.24e+001,
1.23e+004, 1.73e-001)
Also possible to force a decimal point to appear by using stream manipulator
showpoint. 当使用 showpoint 时，表示打印浮点数的小数点和小数位数，即使
显示的数值没有小数点。
cout << fixed << showpoint << setprecision(2);
c = c + 3;
等於
c += 3;
int main()
{
int A=2;
int B=2;
A++;
++B;
printf("A=%d
return 0;
B=%d \n",A,B);
}
兩者 A 與 B 的輸出均是 3
但只要我們是以表示式來使用，效果就不一樣了。
int main()
{
int A = 2;
int B = 2;
int C = A++;
int D = ++B;
printf("C=%d
D=%d \n",C,D);
return 0;
}
A++：意思是先把 A 放到 C，再執行 A=A+1 的動作。
因為 A 先放到 C，所以 C 的值會是 2
++B：意思是先再執行 B=B+1，再把 B 放到 D。
因為 B 會先執行 B=B+1 的動作，所以 D 的值會是 3
pow(x, y) calculates the value of x raised to the yth power
setw() 函数只对紧接着的输出产生作用。
当后面紧跟着的输出字段长度小于 n 的时候，在该字段前面用空格补齐，当输
出字段长度大于 n 时，全部整体输出。