String Functions in C

Stringfns.c

#include<stdio.h>
#include<stdlib.h>
#define ARRAY_SIZE 15
typedef enum {false, true} bool;
int leng(char *ipstr)
{
    int i = 0;
    while(ipstr[i] != '\0')
        i++;
    return i;
}
char *concat(char *str1, char *str2)
{
     int leng1, i;
     leng1 = leng(str1);
     for(i = leng1; *str2 != '\0'; i++, str2++)
     {
         str1[i] = *str2;
     }
     str1[i] = '\0';
     return str1;
}
bool compare(char *str1,char *str2)
{
     int leng1, leng2, i, count = 0;
     leng1=leng(str1);
     leng2=leng(str2);
     if(leng1 == leng2)
     {
         for(i = 0; i < leng1; i++)
         {
             if(str1[i] != str2[i])
             {
                 return false;
             }
         }
         return true;
     }
     else
     {
         return false;
     }
}
char *reverse(char *str1)
{
    int leng1, i, j, midleng;
    char temp;
    leng1 = leng(str1);
    j = leng1 - 1;
    midleng = leng1 / 2;
    for(i = 0; i < midleng; i++, j--)
    {
        temp = str1[i];
        str1[i] = str1[j];
        str1[j] = temp;
    }
    return str1;
}
int main()
{
    char str1[ARRAY_SIZE],str2[ARRAY_SIZE],*resultstr;
    int length=0,i=0,choice=0,result=-99;
    printf("\n\n\tChoose the operation you need to perform...");
    printf("\n\n\t1.StringLength\n\t2.StringReverse\n\t3.StringConcatenation\
              \n\t4.StringCompare\n\n\tYour Choice(in numbers) : ");
    scanf("%d",&choice);
    switch(choice)
    {
    case 1:
        printf("\n\n\tEnter the input string\n\n\t");
        scanf("%s",str1);
        length=leng(str1);
        printf("\n\n\t The length of the string is %d",length);
        break;
    case 2:
        printf("\n\n\tEnter the input string\n\n\t");
        scanf("%s",str1);
        resultstr=reverse(str1);
        printf("\n\n\t The reversed string is %s",resultstr);
        break;
    case 3:
        printf("\n\n\tEnter two input strings\n\n\t");
        scanf("%s %s",str1,str2);
        resultstr=concat(str1,str2);
        printf("\n\n\t The concatenated string is %s",resultstr);
        break;
    case 4:
        printf("\n\n\tEnter two input strings\n\n\t");
        scanf("%s %s",str1,str2);
        result=compare(str1,str2);
        printf("\n\n\t The result is %d",result);
        break;
    }
}