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统计字符个数

#include <stdio.h>
int main()
{
    char c;
    int count=0;
    while((c=getchar())!='\n')
    {
        count++;
    }
    printf("\n");
    printf("There are %d characters.\n", count);
    return 0;
}

用for循环的处理办法

#include <stdio.h>
int main()
{
   char c;
   int i;
   for(i=0; (c=getchar())!='\n';i++)
      putchar(c+4);
    printf("\n");
    printf("There are %d characters.\n", i);
    return 0;
}

统计数字字符个数

#include <stdio.h>
int main()
{
    char c;
    int n=0;
    printf("Input a sentence: ");
    while((c=getchar())!='\n')
    {
        if(c>='0'&&c<='9') n++;
    }
    printf("There are %d number characters.\n", n);
    return 0;
}