Reverse the String without using built-in function in C

 

Reverse the String Using C program

C Program:

#include<stdio.h> #include<string.h> int main() { char str[10]; gets(str); int n,i; n=strlen(str); char a[n]; int x; x=n/2; for(i=0;i<x;i++) { a[i]=str[i]; str[i]=str[n-i-1]; str[n-i-1]=a[i]; } printf("%s",str); return 0; }

Output 1:

Output 2:

From the above program,

ü Let us take the string as "WinG" which is stored in the variable str[100].

ü n=strlen(str), therefore n=4.

ü a[n] will be the temporary variable.

ü x=n/2 => x=4/2 => x=2 which is used for the iteration purpose.

ü for loop is explained in the below table.

i	i<x	a[i]=str[i]	str[i]=str[n-i-1]	str[n-i-1]=a[i]	i++
0	0<2	a[0]=str[0] a[0]=W	str[0]=str[4-0-1] str[0]=str[3] str[0]=G	str[4-0-1]=a[0] str[3]=a[0] str[3]=W	1
1	1<2	a[1]=str[1] a[1]=i	str[1]=str[4-1-1] str[1]=str[2] str[1]=n	str[4-1-1]=a[1] str[2]=a[1] str[2]=i	2
2	2<2 false	Doesn’t execute

 

ü finally, the string will be printed in the reverse order.

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