C:重新提示向argv[]中输入值-没有错误关闭-凯撒密码

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

void caesar_cipher(char *text, int shift) {
    for (int i = 0; text[i]; i++) {
        if (isalpha(text[i])) {
            char base = isupper(text[i]) ? 'A' : 'a';
            text[i] = (text[i] - base + shift) % 26 + base;
        }
    }
}

int main(int argc, char *argv[]) {
    if (argc != 3) {
        printf("Usage: %s <text> <shift>\n", argv[0]);
        return 1;
    }

    char *text = argv[1];
    int shift = atoi(argv[2]);

    if (shift < 0) {
        printf("Shift value must be non-negative.\n");
        return 1;
    }

    caesar_cipher(text, shift);
    printf("Encrypted text: %s\n", text);

    return 0;
}