c++的helloworld

C++  /  houtizong 发布于 3年前   276

helloworld

#include <iostream>using namespace std ;int main (){        int a , b;        cout << " Please  input two numbers :";        cin >> a >> b;        cout << a << "+" << b << "=" << a + b << endl ;        return 0;}

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直接输入和输出到文件

#include <iostream>#include <fstream>using namespace std;ifstream fin ("sum.in");ofstream fout ("sum.out ");int main (){        int a , b;        fin >> a >> b;        fout << a + b << endl ;        return 0;}

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#include <stdio.h>union {        int a [2];        double b;        char c [8];} x;int main (){        x.c [0] = 'G';        x.c [1] = 'O';        x.c [2] = 'O';        x.c [3] = 'D';        x.c [4] = 'B';        x.c [5] = 'A';        x.c [6] = 'B';        x.c [7] = 'Y';        printf ("int : %d  byte (s)\n" , sizeof (int ));        printf (" double : %d  byte (s)\n" , sizeof ( double ));        printf (" char : %d  byte (s)\n" , sizeof ( char )); //       printf (" bool : %d  bytes (s)\n" , sizeof ( bool ));        printf ("\n");        printf (" integer : %d %d\n" , x.a[0] , x.a [1]);        printf (" real   number : %e\n" , x.b);        printf (" characters : %c%c%c%c%c%c%c%c\n" , x.c[0] , x.c[1] , x.c[2] ,                        x.c[3] , x.c[4] , x.c[5] , x.c[6] , x.c [7]);        printf ("HEX : %X%X%X%X%X%X%X%X\n" , x.c[0] , x.c[1] , x.c[2] , x.c[3] ,                        x.c[4] , x.c[5] , x.c[6] , x.c [7]);        return 0;}~