1 /* 2 对终端进行读写的程序 3 */ 4 5 #include <stdio.h> 6 #include <unistd.h> 7 8 char *menu[] = 9 { 10 "a - add new record", 11 "d - delete record", 12 "q - quit", 13 NULL, 14 };//定义了字符串数组 15 16 int getchoice(char *greet, char *choices[]);//定义了函数原型 17 18 int main()//主函数 19 { 20 int choice = 0; 21 22 if(!isatty(fileno(stdout)))//是终端的话返回1，不指执行循环体 23 { 24 fprintf(stderr,"You are not a terminal! "); 25 exit(1); 26 } 27 28 do 29 { 30 choice = getchoice("Please select an action", menu);//调用函数 31 printf("You have chosen: %c ", choice);//打印选择的字符串 32 } while (choice != 'q'); 33 exit(0); 34 } 35 36 int getchoice(char *greet, char *choices[])//核心函数 37 { 38 int chosen = 0; 39 int selected; 40 char **option; 41 42 do 43 {//先无条件循环一次 44 printf("Choice: %s ",greet);//打印欢迎语 45 46 option = choices;//数组赋值给option 47 while(*option) 48 {//option不为空 49 printf("%s ",*option);//循环打印option 50 option++; 51 } 52 53 //selected = getchar();//获取用户输入单独这句在ubuntu上好像不能截取处合适的字符 54 do{selected=getchar();} 55 while (selected == ' '); 56 57 option = choices;//再次给option赋值为数组 58 while(*option) 59 {//不为空的时候 60 if(selected == *option[0]) //对比数组第一个字母和选择的输入 61 { 62 chosen = 1;// 63 break; 64 } 65 option++; 66 } 67 if(!chosen) {//有匹配的话不执行 68 printf("Incorrect choice, select again "); 69 } 70 } while(!chosen);//有匹配的话不再循环 71 return selected; 72 } 73 //执行效果： 74 /* 75 jason@t61:~/c_program/544977-blp3e/chapter05$ ./a.out 76 Choice: Please select an action 77 a - add new record 78 d - delete record 79 q - quit 80 81 82 83 a 84 You have chosen: a 85 Choice: Please select an action 86 a - add new record 87 d - delete record 88 q - quit 89 d 90 You have chosen: d 91 Choice: Please select an action 92 a - add new record 93 d - delete record 94 q - quit 95 q 96 You have chosen: q 97 jason@t61:~/c_program/544977-blp3e/chapter05$ 98 99 jason@t61:~/c_program/544977-blp3e/chapter05$ ./a.out >file 100 You are not a terminal! 101 102 */
1 #include <stdio.h> 2 #include <unistd.h> 3 4 char *menu[] = { 5 "a - add new record", 6 "d - delete record", 7 "q - quit", 8 NULL, 9 };//定义了字符数组 10 11 int getchoice(char *greet, char *choices[], FILE *in, FILE *out);//定义了函数原形 12 13 int main()//主函数 14 { 15 int choice = 0; 16 FILE * input; 17 FILE * output; 18 19 if (!isatty(fileno(stdout))) {//是终端的话返回-1执行循环体 20 fprintf(stderr,"You are not a terminal, OK. "); 21 } 22 23 input = fopen("/dev/tty", "r");//只读模式打开终端。返回文件流 24 output = fopen("/dev/tty", "w");//指写模式打开终端，返回文件流 25 if(!input || !output) { //出错处理 26 fprintf(stderr,"Unable to open /dev/tty "); 27 exit(1); 28 } 29 30 do { 31 choice = getchoice("Please select an action", menu, input, output); 32 printf("You have chosen: %c ", choice);//调用函数，打印这句话 33 } while (choice != 'q'); 34 exit(0); 35 } 36 37 int getchoice(char *greet, char *choices[], FILE *in, FILE *out)//核心函数 38 { 39 int chosen = 0; 40 int selected; 41 char **option; 42 43 do { 44 fprintf(out,"Choice: %s ",greet); 45 option = choices; 46 while(*option) 47 { 48 fprintf(out,"%s ",*option); 49 option++;//打印数组内容 50 } 51 52 do 53 { 54 selected = fgetc(in);//从输入流获取输入到selected中 55 } while (selected == ' '); 56 57 option = choices; 58 while(*option) 59 {//当数组不为空的时候 60 if(selected == *option[0]) //匹配第一个字符和输入 61 { 62 chosen = 1; 63 break; 64 } 65 option++; 66 } 67 if(!chosen) 68 { 69 fprintf(out,"Incorrect choice, select again "); 70 } 71 } while(!chosen); 72 return selected;//返回匹配的输入 73 } 74 75 //执行效果 76 /* 77 jason@t61:~/c_program/544977-blp3e/chapter05$ ./a.out >file1 78 You are not a terminal, OK. 79 Choice: Please select an action 80 a - add new record 81 d - delete record 82 q - quit 83 a 84 Choice: Please select an action 85 a - add new record 86 d - delete record 87 q - quit 88 q 89 jason@t61:~/c_program/544977-blp3e/chapter05$ cat file1 90 You have chosen: a 91 You have chosen: q 92 93 */
关于怎么重定向到文件中的还是没看懂。应该是跟/dev/tty的性质有关系吧，以后学到再研究。
参考文献：
Linux程序设计 Neil Matthew