Efficient way to multiply with 7 | GeeksforGeeks

We can multiply a number by 7 using bitwise operator. First left shift the number by 3 bits (you will get 8n) then subtract the original numberfrom the shifted number and return the difference (8n – n).


Program:

# include<stdio.h>   int multiplyBySeven(unsigned int n) {      /* Note the inner bracket here. This is needed        because precedence of '-' operator is higher        than '<<' */     return ((n<<3) - n); }

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