1. Write a C expression (or a collection of sequential expressions) that will sw

Question

1. Write a C expression (or a collection of sequential expressions) that will swap the mth and nth byte of the 64-bit quantity (stored as a 64-bit integer, but is really 8 ascii characters). For this problem the index of the least significant byte is 0, and the index of the most significant byte is 7 (so 0 <= n,m <= 7). So if x = “hi calss” = 0x68692063616C7373 (a 64-bit quantity), and we want to swap the ‘a’ and the ‘l’ to get “hi class” we could have n equals 3 and m equals 2, the C expression(s) would return 0x686920636C617373 = “hi class”. You cannot use, division, multiplication, or modulus, relative comparisons (<, >, <=, >=), loops, switches, function calls, macros, conditionals (if or ?:). You are allowed to use all bit level and logic operations, left and right shifts, addition and subtraction, equality and inequality tests, integer constants (<=255), INT_MIN and INT_MAX, and casting between data types. (20 points)

Explanation / Answer

#include <stdio.h>

int main(void) {

char C[10];

int m,n,i;

printf("Enter ASCII CHAR ");

for(i=1;i<9;i++) //for 8 Ascii char

{

scanf("%c",&C[i]);

}

printf("Enter m and n ");

scanf("%d%d",&m,&n);

// swapping using XOR logical operation

C[m]=C[m]^C[n];

C[n]=C[m]^C[n];

C[m]=C[m]^C[n];

for(i=1;i<9;i++)

{

printf("%c",C[i]);

}

return 0;

}

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