c - 查找数组中字符 'a'的索引

Question

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


int main()
{
char hurray[] = "Hooray for all of us"; //Character String
char *hurrayptr = hurray;   //Pinter to array hurray
int i = 0; //Used in for loop to display position and character
int d = 0; //Used in printf statement to count the position 
int k;
int count = 0;
int index;
int f = 0;

printf("\tPosition\t Character"); 

while (hurray[i] > 20) { 

    for (i = 0; i < 20; i++) {  

        printf("\n\t hurray[%d]\t\t  %c", d++, *hurrayptr++); 

    }
}

for (k = 0; hurray[k]!= '\0'; k++)      
    if ('a' == hurray[k]) {  //specifies character 'a' is to be counted

        count++;    
    }
        printf("\n'A' occurs %d times in this array\n", count); 

        hurrayptr = strchr(hurray, 'a');
        index = (int)(hurrayptr - hurray);
        f++;

        printf("The letter 'a' was find in hurray[%d]\n", index);

return 0;
}

我试图让它显示数组 hurray[] 中的元素数量，然后查找数组中“a”出现的次数。然后我需要找到找到的“a”的索引。我只能让它找到第一个“a”，然后它就停止了。我该如何解决这个问题？

Answer 1

这段代码:

hurrayptr = strchr(hurray, 'a');
index = (int)(hurrayptr - hurray);
f++;

printf("The letter 'a' was find in hurray[%d]\n", index);

仅查找第一个字母。您需要循环执行这些步骤:

hurrayptr = strchr(hurray, 'a');
do {
    index = (int)(hurrayptr - hurray);
    printf("The letter 'a' was find in hurray[%d]\n", index);
    hurrayptr = strchr(hurrayptr+1, 'a');
} while (hurrayptr);

对 strchr 的第一次调用从字符串的开头开始，循环内部的调用开始查找找到的最后一个实例。

此外，这不是必需的:

while (hurray[i] > 20) {

您有一个 for 循环，它已经打印了所有字符。 while 是多余的。