Question

我正在尝试学习如何在C中编码，并且我试图从输入数组向数组中添加唯一字符，只有当该字符在唯一数组中不存在时才会以非常简单的方式。

我真的很难过，如果能够正确地思考，我会很感激。这是我的代码：

    /* get each character and how many times it shows up 
 * to do this we need to store each unique char in a char array, and the count for each
 * unique char in an int array */
char unique_chars[count];
for(int each = 0; each < count; ++each)
    unique_chars[each] = '0';

/* count is the total number of chars stored in theinput array. */
int no_times = 0;

for(int each = 0; each < count; ++each)
{
    if(theinput[each] != unique_chars[each])
        unique_chars[each] = theinput[each];
    if(theinput[each] == unique_chars[each])
        continue;

    for(int item = 0; item < count; ++item){
        if(theinput[each] == unique_chars[item]){
            ++no_times;
        } 
    }
    printf("%c is in theinput array %d times.\n", theinput[each], no_times);
    no_times = 0;
}
 /* print all the values in the unique_chars array*/
 printf("values in unique_chars are: \n");
 for(int each = 0; each < count; ++each);
 printf("\n");       

 return 0;

这是我尝试过的很多事情之一。它返回以下内容：

./uniquely
exsss
The characters typed in are: exsss
Number of characters are: 6
values in unique_chars are: 
e x s s s

请问我该怎么做？

Answer 1

您应该按如下方式重新编写程序的算法：

set count_unique to zero
for each index in the input
    set count to zero
    go through input to again using index i
        if input[index] is the same as input[i]
            count++
    if count is 1 after the loop
        unique_chars[count_unique++] = input[index]
for each index from zero to count_unique
    print unique_chars[index]

但是，这是很长的路要走。简短的方法是遍历输入一次，增加计数，然后遍历计数，并打印值为1的索引：

int counts[256];
for (int i = 0 ; i != count ; i++) {
    counts[(unsigned)input[i]]++;
}
for (int i = 0 ; i != 256 ; i++) {
    if (counts[i] == 1) {
        printf("%c ", i);
    }
}
printf("\n");

仅当元素不存在时才向C数组添加元素

1 个答案: