程序代码：

#include <stdio.h>
#include <ctype.h>
int main(void)
{
    float x[10],y[10],z;
    char q;
    int i,j,falg=0;
    printf("--简单计算器--\n");
    printf("--输入数据规则:1+1,输入时:1,+,1--\n");
    while (scanf("%s,%c,%s",&x,&q,&y))
    {
        for (i==0;x[i]!=0;i++)
        {
            if (i==0&&(x[i]!='+'||x[i]!='-'))
            {
                i++;
            continue;
            }
            if (x[i]='.')
            {
                falg++;
                if (falg>1)
                {
                    break;
                }
                else if (flag==1)
                {
                    continue;
                }
                j=isdigit(x[i]);
                if (j==0)
                {
                    break;
                }
            }
        }
        if (j!=0)
            printf("是数字\n");
            else
            printf("非数字\n");
    }
    return 0;
}

程序代码：

#include <stdio.h>
#include <ctype.h>
int main(void)
{
    float x[10],y[10],z;
    char q;
    int i,j,flag=0;
    printf("--简单计算器--\n");
    printf("--输入数据规则:1+1,输入时:1,+,1--\n");
    while (scanf("%s,%c,%s",&x,&q,&y))
    {
        for (i=0;x[i]!=0;i++)
        {
            if (i==0&&(x[i]!='+'||x[i]!='-'))
            {
                i++;
            continue;
            }
            if (x[i]='.')
            {
                flag++;
                if (flag>1)
                {
                    break;
                }
                else if (flag==1)
                {
                    continue;
                }
                j=isdigit(x[i]);
                if (j==0)
                {
                    break;
                }
            }
        }
        if (j!=0)
            printf("是数字\n");
            else
            printf("非数字\n");
    }
    return 0;
}

程序代码：

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

int main()
{
    double x;
    char buf[31], *endptr;

    while (scanf(" %30[^\n]", buf) == 1) {
        x = strtod(buf, &endptr);

        if (endptr == buf)
            fprintf(stderr,
                "Convertion failed: Can't convert `%s\' to a double!\n",
                buf);
        else if (*endptr != '\0')
            fprintf(stderr,
                "Convertion failed: `%s\' was converted to %lg, "
                "and the rest `%s\' is discarded.\n",
                buf, x, endptr);
        else
            fprintf(stdout,
                "Convertion succeeded: `%s\' was converted to %lg\n",
                buf, x);
    }

    return 0;
}