1、

#include <stdio.h>

void del_dit(char x[])
{
    int i = 0, j = 0;
    char tmp[129];
    while(x[i])
    {
        if((x[i] - '0') < 0 || (x[i] - '0') > 9)
        {
            tmp[j] = x[i];
            j++;
        }
        i++;
    }
    while(i-- > 0)
        x[i] = '\0';
    for(i = 0; i < j; i++)
    {
        x[i] = tmp[i];
    }
}

int main(void)
{
    char str[129];
    printf("str:  "); scanf("%s", str);
    
    del_dit(str);
    printf("delete digit result: %s\n", str);
    return 0; 
}

 

2、

#include <stdio.h>

void del_dig(char x[])
{
    int i = 0;
    while(x[i])
    {
        if(x[i] >= '0' && x[i] <= '9')
            printf("");
        else
            putchar(x[i]);
        i++;
    }
}

int main(void)
{
    char str[128];
    printf("str:  "); scanf("%s", str);
    
    del_dig(str);
    return 0;
}

 

3、

#include <stdio.h>

void del_dig(char x[])
{
    int i = 0;
    while(x[i])
    {
        if(x[i] >= '0' && x[i] <= '9')
            i++;
        else
        {
            putchar(x[i]);
            i++;
        }
    }
}

int main(void)
{
    char str[128];
    printf("str:  "); scanf("%s", str);
    
    del_dig(str);
    return 0;
}