Reversing a String in C

#include<stdio.h>
main()
{
        int str_length();
void rev_str();
char array[80];
int i,nchars;
puts("Enter a string\n");
gets(array);
nchars=str_length(array);
printf("No. of characters in %s = %d\n",array,nchars);
rev_str();
getch();
return 0;
}


int str_length(str)
char str[];
{
int i=0,len=0;
while(str[i]!='\0')
{
len++;
i++;
}
return(len);
}




void rev_str(str,nc)
char str[];
int nc;
{
int i,count=nc-1;
char tempstr[80];
for(i=(nc-1);i>=0;i--)
{
tempstr[count-1]=str[i];
}
printf("Reversed String is : %s = ",tempstr);
}