Question

求C程序代码：编写函数int fun(char *str,char ch)，统计字符串str中 指定字符ch的个数，统计结果作为函数

已有部分程序代码（有的部分不能改动）：#include<stdio.h>
void NONO();
int fun(char *str,char ch)
{
}
void main()
{char a[100],b;
puts("Please input a string:");
gets(a);
puts("Please input a character:");
b=getchar();
printf("n=%d\n",fun(a,b));
NONO();
}
void NONO()
{FILE *rf,*wf;char a[80],b;int i;
rf=fopen("in2.dat","r");
if(rf==NULL)
{puts("No exist in2.dat");return;}
wf=fopen("out2.dat","w");
for(i=0;i<3;i++)
{b=fgetc(rf);
fgets(a,80,rf);a[strlen(a)-1]=0;
fprintf(wf,"%d\n",fun(a,b));
}
fclose(rf);fclose(wf);
}

Answer 1

int fun(char *str,char ch)
{
int i,k=0;
for(i=0;str[i];i++)
if (str[i]==ch) k++;
return k;
}

Answer 2

int fun(char *str,char ch) {
int n = 0;
char *p = str;
while(*p) {
if(*p == ch) ++n;
++p;
}
return n;
}

Answer 3

int fun(char *str,char ch)
{
int conut=0,i;
for(i=1;i<=100;i++)
if(*str++==ch) conut++;
return conut;
}