题解 | #字符个数统计#

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

int main(void) {
    int checkArray[5000] = {0};
    int counter = 0;
    char* string = (char*)malloc(sizeof(char) * 1000);
    gets(string);
    int len = strlen(string);
    for (int i = len - 1; i >= 0; i--) {
        if (checkArray[string[i]]) continue;
        if (string[i] >= 0 && string[i] <= 127) {
            counter++;
            checkArray[string[i]] = 1;
        }
    }
    printf("%d\n", counter);
    free(string);
    return 0;
}