C语言读取文件字符串统计字母个数

#include 
void hello(char one, FILE*fp )
{
char letter;
int num=0, ret;
 
 
while(!feof(fp))
{
if(letter==one||letter+32==one)
num++;
 
ret = fscanf(fp, "%c", &letter);
if (ret == EOF)
break;
 
}
 
for(int i=0;i
{
	printf("%c",one);
}
if(num!=0)
{
	printf("\n");
}
}
int main()
{
FILE *fp;
if((fp=fopen("input.txt", "r"))==NULL){
return -1;
}
char str[26];
int i=0;
str[0]='a';
for (i=0; i<26; i++){
str[i] = 'a' + i;
hello(str[i], fp);
rewind(fp);
}
fclose(fp);
return 0;
}