如何用高集合的函数解决？

题目一不知用什么函数做冒泡排序，题目二不知怎么显示字母
#include
int main(int argc, const char* argv[])
{
char a[50] = { 0 };
gets_s( a);
int i = 0, zm = 0, kg = 0, sz = 0, qt = 0;
for (i = 0; a[i] != '\0'; i++)
{
if (a[i] >= 'A' && a[i] <= 'Z' || a[i] <= 'z' && a[i] >= 'a')
zm = zm + 1;
else if (a[i] == ' ')
kg = kg + 1;
else if (a[i] >= '0' && a[i] <= '9')
sz = sz + 1;
else
qt = qt + 1;
}
printf("英文字母个数：%d\n", zm);
printf("空格符号个数：%d\n", kg);
printf("数字符号个数：%d\n", sz);
printf("其他符号个数：%d\n", qt);
return 0;
}