在C中的char数组中搜索char值[关闭]

Question

我正在课堂上学习 c 语言，我创建了一些代码来在其他数组中查找某个数字，但是当我尝试使用 char 值时，我的代码与使用 int 值的方式不同。

这是我的代码：

#include<stdio.h>

int main () {
    int  num, i, j;
    char a[99], ele;

    printf("Enter the Character element:");
    // get the length of array by the num value
    scanf("%d", &num);

    printf("Enter the values: \n");
    // a loop for getting values for our a[array] line by line
    for ( i = 0 ; i < num ; i++ ) {
        // get value by index i for array a index by index
        //printf("%d\t", (i+1));
        //if ( i + 1  == num ) {
        //    scanf("%c", &a[i]);
        //} else {
            scanf("%c", &a[i]);
        //}

    }

    printf("Enter the Character elements to be searched:");
    // get the value for ele, to use ele for searching inside our a[array]
    scanf("%c", &ele);

    // we need to set i to 0 for our while loop
    j = 0;
    // use the while loop to
    while ( j < num && ele != a[j]) {
        j++;
    }
    if ( j < num ) {
        printf("Character found at the location = %d\n\n\n", j + 1);
    } else {
        printf("Character Not Found!\n\n\n");
    }
    return 0;

}

我尝试修复了很多次，但每次都出现错误，所以上面的那个是有效的，但它在输入过程中会限制一些输入值。

Answer 1

您的程序中有一个问题导致了令人惊讶的行为：

• scanf("%d", &num) 从标准输入中读取一个数字，但将用户键入的换行符留作待读取的下一个字符。
• 对scanf("%c", &a[i]); 的进一步调用会读取此待处理的换行符和num-1 来自用户的更多字符，其余的输入待处理...
• 最后的 scanf("%c", &ele); 读取标准输入中待处理的任何字节，无论是来自用户的字符还是待处理的换行符。

因此程序的行为就好像它没有执行最后一个scanf()。

您应该使用fgets() 一次读取用户的一行输入，或者使用循环刷新待处理的换行符：

#include <stdio.h>

int main() {
    int num, i, c;
    char a[99], ele;

    printf("Enter the number of character:");
    // get the length of array by the num value
    if (scanf("%d", &num) != 1 || num < 0 || num > 99)
        return 1;

    // consume the rest of the line typed by the user
    while ((c = getchar()) != EOF && c!= '\n')
        continue;

    printf("Enter the characters on a single line: \n");
    // a loop for getting values for our a[array]
    for (i = 0; i < num; i++) {
        if (scanf("%c", &a[i]) != 1)
            return 1;
    }

    // consume the rest of the line typed by the user
    while ((c = getchar()) != EOF && c!= '\n')
        continue;

    printf("Enter the character to be searched: ");
    // get the value for ele, to use ele for searching inside our a[array]
    if (scanf("%c", &ele) != 1)
        return 1;

    // consume the rest of the line typed by the user
    while ((c = getchar()) != EOF && c!= '\n')
        continue;

    // use a for loop
    for (i = 0; i < num && ele != a[i]; i++) {
        i++;
    }
    if (i < num) {
        printf("Character %c found at the offset %d\n\n\n", ele, i);
    } else {
        printf("Character %c Not Found!\n\n\n", ele);
    }
    return 0;
}

Answer 2

感谢WhozCraig、user3121023 的建议，scanf(" %c", &a[i]); 和 scanf(" %c", &ele); 中的空格会产生一些不需要的输入，所以这是我的代码，它的工作方式很有魅力。 :))

我只是在%c 之前添加空格，一切都很好。

#include<stdio.h>

int main () {
    int  num, i, j;
    char a[99], ele;

    printf("Enter the Character element:");
    // get the length of array by the num value
    scanf("%d", &num);

    printf("Enter the values: \n");
    // a loop for getting values for our a[array] line by line
    for ( i = 0 ; i < num ; i++ ) {
        // get value by index i for array a index by index
        printf("%d\t", (i+1));
        scanf(" %c", &a[i]);


    }

    printf("Enter the Character elements to be searched:");
    // get the value for ele, to use ele for searching inside our a[array]
    scanf(" %c", &ele);

    // we need to set i to 0 for our while loop
    j = 0;
    // use the while loop to
    while ( j < num && ele != a[j]) {
        j++;
    }
    if ( j < num ) {
        printf("Character found at the location = %d\n\n\n", j + 1);
    } else {
        printf("Character Not Found!\n\n\n");
    }
    return 0;

}