练习 1-14 编写一个程序，打印输入中各个字符出现频度的直方图。

 

1 #include 
     
       2  3 /* count digits, white space, others */ 4  5 int main(int argc, char const *argv[]) 6 { 7     int c, i, j, nwhite, nother; 8     int ndigit[10]; 9 10     nwhite = nother = 0;11     for (i = 0; i < 10; ++i) {12         ndigit[i] = 0;13     }14 15     while ((c = getchar()) != EOF) {16         if (c >= '0' && c <= '9') {17             ++ndigit[c-'0'];18         } else if (c == ' ' || c == '\n' || c == '\t') {19             ++nwhite;20         } else {21             ++nother;22         }23     }24 25     for (i = 0; i < 10; ++i) {26         printf("%d:", i);27         for (j = 0; j < ndigit[i]; ++j) {28             printf("*");29         }30         printf("\n");31     }32     printf("w:");33     for (i = 0; i < nwhite; ++i) {34         printf("*");35     }36     printf("\no:");37     for (i = 0; i < nother; ++i) {38         printf("*");39     }40     printf("\n");41 42     return 0;43 }