求主函数分析和自定义函数分析

main()
{
char str[80],c[80];
void cpy();
printf("\n\nPlease input a string: ");
gets(str);
printf("\n\n%s\n",str);
cpy(str,c);
printf("\n The vowel in the string is: %s\n",c);
}
void cpy(s,c)
char s[],c[];
{int i,j;
for(i=0,j=0;s[i] !='\0';i++)
if(s[i]=='a'||s[i]=='A'||s[i]=='e'||s[i]=='E'||
s[i]=='i'||s[i]=='I'||s[i]=='o'||s[i]=='O'||
s[i]=='u'||s[i]=='U')
{c[j]=s[i];
j++;}
c[j]='\0';
}