“C++”如何打开用变量命名的文件？

Posted 2023-02-15

参考技术A C++ 和 c 类似，文件名可以用变量。\\x0d\\x0a例如 char a[5][20]="abc.txt","xyz.txt","a2b.txt","123.txt","789.txt";\\x0d\\x0a有5 个文件名。 用 a[0] 就用了 abc.txt\\x0d\\x0a下面作为 建立和写 文件 打开：\\x0d\\x0a#include\\x0d\\x0a#include \\x0d\\x0ausing namespace std;\\x0d\\x0a#include \\x0d\\x0amain()\\x0d\\x0aFILE *fp;\\x0d\\x0achar a[5][20]="abc.txt","xyz.txt","a2b.txt","123.txt","789.txt";\\x0d\\x0aint x=5;\\x0d\\x0aif ( (fp=fopen(a[0],"w"))==NULL)\\x0d\\x0aprintf("open %s error !",a[0]);\\x0d\\x0areturn 0;\\x0d\\x0a;\\x0d\\x0afprintf(fp,"%d\n",x);\\x0d\\x0afclose(fp);\\x0d\\x0acout << "output in " <\\x0d\\x0a作为输入文件打开方法：\\x0d\\x0aifstream ifs;\\x0d\\x0aifs.open (a[0], std::ifstream::in); \\x0d\\x0a作为输出文件打开方法：\\x0d\\x0aofstream ofs;\\x0d\\x0aofs.open (a[0], std::ofstream::out）；\\x0d\\x0a===\\x0d\\x0a若讨论字符串运算：\\x0d\\x0achar name[80];\\x0d\\x0achar a[10]="123";\\x0d\\x0aint x=4567;\\x0d\\x0asprintf(name,"%s.txt",a);\\x0d\\x0aname 就变 "123.txt"\\x0d\\x0asprintf(name,"%d.txt",x);\\x0d\\x0aname 就变 "4567.txt"\\x0d\\x0a打开语句里用name就可以