C++ Multiply without multiply
A couple of ways for write multiply, without using multiply…
int multiply(int value,int mul) {
int ret=0;
int mulabs = mul;
if(mulabs < 0) mulabs = 0 – mulabs;
for(int n=0;n<mulabs;n++) {
ret += value;
}
if(mul < 0) ret = 0-ret;
return ret;
}
int multiply2(int value,int mul) {
int total=0;
for(int n=30;n>=0;n–) {
if((mul & (1 << n)) > 0) {
total += value << n;
}
}
return total;
}
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