Question

我对这个程序的输出有些麻烦。我需要在一行上打印动词，并且我需要在没有动词的情况下打印单独的语句。对于前者

"talk and walk"应该打印"The verbs are: talk walk"

而"hello there"应打印"There are no verbs"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int binary_search(char *list_of_words[], int size, char *target){
    int bottom= 0;
    int mid;
    int top = size - 1;
    int found = 0;

    while(bottom <= top && !found){
        mid = (bottom + top)/2;
        if (strcmp(list_of_words[mid], target) == 0){
            //printf("%s found at location %d.\n", target, mid+1);
            found = 1;
        } else if (strcmp(list_of_words[mid], target) > 0){
            top    = mid - 1;
        } else if (strcmp(list_of_words[mid], target) < 0){
            bottom = mid + 1;
        }
    }
    if (found == 1)
        return mid;
    else
        return -1;
}

int main(int argc, char* argv[]){
    char *input = strtok(argv[1], " \"\n");
    char *verbs[5] = { "do", "make", "take", "talk", "walk" };
    int position;
    int check = 0;
    while (input != NULL) {
        //printf("%s\n", input);
        position = binary_search(verbs, 5, input);
        if (position != -1)
            printf("The verbs are: %s\n", verbs[position]);
            check = 1;
        input = strtok(NULL, " ");
    }
    if (check == 0){
        printf("There are no verbs\n");
    }
    return 0;
}

有什么想法吗？

Answer 1

它似乎工作正常，但您需要在

周围添加括号

    if (position != -1)
        printf("The verbs are: %s\n", verbs[position]);
        check = 1;

喜欢

    if (position != -1) {
        printf("The verbs are: %s\n", verbs[position]);
        check = 1;
    }

否则检查总是在循环中设置为1。

如果您不想重复“动词是：”，请添加一个检查

    if (position != -1) {
        if (first) {
            printf("The verbs are:");
            first = 0;
            check = 1;
        }
        printf(" %s", verbs[position]);

    }

Answer 2

int main(int argc, char* argv[]){
    char *input = strtok(argv[1], " \"\n");
    char *verbs[5] = { "do", "make", "take", "talk", "walk" };
    char match[5] = {0};
    int position;
    int check = 0;
    while (input != NULL) {
        //printf("%s\n", input);
        position = binary_search(verbs, 5, input);
        if (position != -1){
            //printf("The verbs are: %s\n", verbs[position]);
            match[position]=1;//match[position] = check = 1;
            check = 1;
        }
        input = strtok(NULL, " ");
    }
    if (check == 0){
        printf("There are no verbs\n");
    } else {
        int i;
        printf("The verbs are: ");
        for(i=0;i<5;++i)
            if(match[i])
                printf("%s ", verbs[i]);
        printf("\n");
    }
    return 0;
}

Answer 3

如果您对完成搜索更感兴趣，而不是自己实施（即假设“实施搜索”不是您的实际任务），您应该使用标准库的鲜为人知的英雄{{ 3}}

请注意，这需要对输入数据（您正在搜索的数组）进行排序，但您的搜索似乎是因为您已经在进行二进制搜索。

使用C中的printf格式化二进制搜索的输出？

3 个答案: