C语言，用自定义函数实现：给定字符串…输出其长度

#include void change(char *str);int counter(const char *str);void main(){ char *str=NULL; int len=0; str=(char *)malloc(MAX*sizeof(char)); fprintf(stdout,"enter the letters,\n"); scanf("%s",str); len=counter(str); fprintf(stdout,"the length of the letters is %d",len); change(str); printf("%s",str);}int counter(const char *str){ int len=0; while(*str++!='\0') len++; return len;}void change(char *str){ while(*str++!='\0'){ if (islower(*str)) *str+='A'-'a';}}

#includeint length(const char* str)
{
int i=0;
while( str[i]!='\0' )
i++;
return i;
}int main()
{
const char* test = "my test";
printf("%d", length(test));
}

#include
int longs(char *s)
{
int i=0,n=0;
for(i=0;*(s+i)!='\0';i++)
n++;
return(n-1);
}

void main()
{
char *s;
char c[100];
int num;
s=c;
gets(c);
num=longs(s);
printf("%d",num);
}