c - 如何在C中连接数组中的字符

Question

我想从键盘获取一个值(1、2 或 3 位数字)，并希望在控制台上打印出该值。

我有，

char val[i] // value from a Keypad from 1 through 120
            // so, val[i] could be one, two or three digit number.

我想做的是，

if (val[i] == 1)
    printf("The number you got is %d", val[i]); // prints "The number you got is 1"
else if ((val[i] == 2)
    printf("The number you got is %d", val[i]); // prints "The number you got is 2"
    .
    .
else if ((val[i] == 10)
    printf("The number you got is %d", val[i]); // prints"The number you got is 10"
    .
    .
else if ((val[i] == 120)
    printf("The number you got is %d", val[i]); // prints"The number you got is 108"
else    printf("Error!");               // prints "Error!"

请帮帮我。预先感谢您的帮助。

Answer 1

应该没问题

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
int isNumber(char* s)
{
    for (int i = 0; i < strlen(s); i++)
        if (isdigit(s[i]) == 0)
            return 0;

    return 1;
}

int main()
{
    char * a = (char*) malloc(4);
    scanf("%s",a);

    int i = atoi(a);

    if(isNumber(a) && i>= 1 && i <= 120)
    {
        printf("The number you got is %d\n", i);
    } else printf("Error!");
}

在我的机器上:

Input : 120

Output : The number you got is 120

Input: 12A

Output : Error!